Yes as Daniel B. Wallace explains, the imperfect tense not only indicates the Word existed before the created world, it would be the correct verb to use to make that statement:
As a tense of the first principal part, the imperfect mirrors the present tense both in its general aspect and its specific uses (the only difference being, for the most part, that the imperfect is used for past time).
Like the present tense, the imperfect displays an internal aspect. That is, it portrays the action from within the event, without regard for beginning or end. This contrasts with the aorist, which portrays the action in summary fashion. For the most part, the aorist takes a snapshot of the action while the imperfect (like the present) takes a motion picture, portraying the action as it unfolds. As such, the imperfect is often incomplete and focuses on the process of the action.
With reference to time, the imperfect is almost always past. (Note that since the imperfect only occurs in the indicative mood, this tense always grammaticalizes time.) However, occasionally it portrays time other than the past (e.g., the conative imperfect may have this force to it sometimes; also the imperfect in second class conditions connotes present time - but such is due more to the aspect than the element of the tense). In general the imperfect may be diagrammed as follows:
Therefore, "In the beginning was the Word and..." not only communicates the preexistence of the Word, it does so "without regard for beginning or end." Moreover, if the text next moved to creation, as in Genesis 1:1, the impression would be the Word was before God:
John 1:1 In the beginning was the Word and...
Genesis 1:1 In the beginning..................God made the heavens and the earth
Of course John does not permit the reader to reach that conclusion because he immediately continues using the imperfect to convey an internal aspect, expressed not as action but as relationship with God:
1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 This One was in the beginning with God.
Verse 2 completes a single thought (more below) which begins with three statements about the Word linked with καὶ before closing with a fourth statement without καὶ. Given the context, the use of the imperfect suggests John's καὶ is explicative,
2which is better understood to mean "that is" and may be illustrated using Wallace's template:
The internal aspect of the imperfect focuses on the relationship between the Word and God. All are "in the beginning" before any mention of creation. Only after establishing the relationship between the Word and God does John write about things and man. In doing so he effectively "envelops" the creative work of the Genesis account:
Gen 1:1a In the beginning...
John 1:1 In the beginning was the Word and the Word was with God and the Word was God
John 1:2 This was in the beginning with God...
Gen 1:1b ...............................God made the heavens and the earth
Gen 1:2-31 The first six days
John 1:3 All things were made by Him and without Him was not anything made that was made
John 1:4 In Him was life and the life was the light of men
To the extent John had Genesis in mind, one concludes he used verse 3 to summarize Genesis 1b-31. Then he spoke not of the seventh day, but of the life and light, or light and life of men
3symbolic of the Sabbath which is eternal (e.g. Exodus 31:13).
The Aorist and Perfect
The imperfect ἦν is not used exclusively in 1:1-4 and to appreciate how it is used its placement among the other verbs must be considered:
In the Majority and Received Text the tense shifts in verse 3, interrupting the uses which otherwise would flow logically through verse 4:
1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 This One was in the beginning with God...4 In Him was life, and the life was the light of mankind [or, In Him was life, and the light was the life of mankind]. [DLNT]
As seen above, verse 3, which describes creation, has been "inserted" such that the train of thought is interrupted. The insertion is composed with the aorist and the perfect:
The force of the perfect is simply that it describes an event that, completed in the past (we are speaking of the perfect indicative here), has results existing in the present (i.e., in relation to the time of the speaker). BDF suggests that the perfect tense "combines in itself, so to speak, the present and the aorist in that it denotes the continuance of completed action." It is incorrect, however, to say that the perfect signifies abiding results; such conclusions belong to the realm of theology, not grammar.
Romans has an example showing how creation in the past remains active in the present:
Because the thing known of God is evident in them, for God made it evident to them. For His invisible things— both His eternal power and divine-nature— are clearly-seen, being understood since the creation of the world in the things made, so that they are without-excuse. (Romans 1:19-20)
Things made have results existing in the present. The results are God's eternal power and divine nature which are not "things" as such, and yet which are clearly seen and leave man without excuse (to know there is a God with eternal power having a divine nature).
John employs the same sequence. What came into being (ἐγένετο - aorist) has results existing in the present (γέγονεν - perfect). He too has a two-fold conclusion: the Word which was God, was both the life and light and the light and life of men. There is a difference though. Romans says the created world is still testifying about God, but John's conclusion in the imperfect implies those are in the past. This is not contradictory because the Word will become flesh. Historically, the Word as the light and life of men is in the past because the Word was coming into the world. John claims it is this Gospel which now leaves men without excuse (John 20:31).
Because John continues to use the imperfect after verse 4, it necessary to consider how those fit within the overall structure. As Wallace states, "occasionally it portrays time other than the past..." This may justify a different reading of 1:1-4, as noted in this answer (emphasis added):
The Greek word is ην. It is also found at J 1:10. In verse 9, the Word is coming into the world. Then in 10, he was (ην) the world. His being in the world did not precede his arrival. If we apply this to J 1:1, he did not precede the beginning.
This argument is straight forward. If comparing vv. 8-10 and 14 to v. 1, the imperfect cannot mean the Word was not present before the beginning. Here is the use in question:
8 That one was not the Light, but came in order that he might testify concerning the Light — 9 the true Light which gives-light-to every person was coming into the world. 10 He was in the world, and the world came-into-being through Him, and the world did not know Him. 11 He came to His own things, and His own ones did not accept Him.
14 And the Word became flesh and dwelt among us, and we saw His glory— glory as of the only-born from the Father, full of grace and truth.
The apparent contradictory use is resolved by considering the overall structure which as Marie-Émile Boismard diagrammed, "forms a sort of parabola:"
(a) The Word 1-2 ● ● 18 The Son in (a')
with God. the Father
(b) His role of 3 ● ● 17 Role of re- (b')
(c) Gift to men 4-5 ● ● 16 Gift to men (c')
(d) Witness of J-B 6-8 ● ● 15 Witness of J-B (d')
(e) The coming of the 9-11 ● ● 14 The Incarnation (e')
Word into the World
(f) By the Incarnate Word we become children of God
Others would call Boismard's structure a chiasm, but his term was "construction by envelopment"
6 because it mirrored the actual events:
...it becomes possible to grasp the internal movement which animates the whole Prologue: the thought leaves God, as so to return to God, after touching the earth. The Word was in God, with God; then he comes towards us men...He seems to detach himself from God who sends him forth, progressively, as if he intends to accustom men, little by little to his presence. Once he has come upon earth he communicates to us that divine life which makes us children of God; that is the centre of the Prologue, the bond of the New Alliance that the Word has come to tighten between God and men, Then the Word, called henceforward the only-begotten Son, reascends to the bosom of the Father, drawing us in his wake to lead us to God...
So everything after the center (vv. 12-13) is about the Word as the Son returning to the Father and, John uses the Gospel to explain how His being in the world did precede His arrival:
Now He said this concerning the Spirit, Whom the ones having believed in Him were going to receive. For the Spirit was not yet given, because Jesus was not yet glorified. (7:39)
And now Father, You glorify Me with Yourself with the glory which I was having with You before the world was. (17:5)
“Father, as to what You have given to Me, I desire that those ones also may be with Me where I am, in order that they may be seeing My glory which You have given to Me because You loved Me before the foundation of the world. (17:24)
The glory John beheld (1:14) was the Word resurrected in the flesh who dwelt among them (Chapter 21). They saw the only-born of the Father, the only one the Father raised to life who was full of grace and truth.
The use of the imperfect to describe the Word before His crucifixion (vv. 8-11) and the aorist after (v. 14) are the proper tenses. Using Wallace's examples, the imperfect is the motion picture of His life on earth before death and the aorist is a snapshot of His life on earth after Resurrection. And what was (8-11) has been eternally replaced when it was resurrected in the flesh.
In the beginning was the Word... uses the imperfect as Wallace says to grammaticalize time and means the Word was, and is, eternal. After all, is necessarily predates was. That is, unless the Word first is, it cannot be described as "was."
However, after this the imperfect is more often used to emphasize relationship, not time. The Word was with God; the Word was God; in Him was life; life was light and life; He was the true light; this was He of whom I spoke; He was not the light.
There are only three places where time is the primary meaning:
1a: In the beginning was the Word...
10: He was in the world, and the world came-into-being through Him,
and the world did not know Him.
15: John testifies concerning Him, and has cried-out saying,
“This One was the One of Whom I said, ‘The One coming after me
has become ahead of me, because He was before me’”.
In each of these three, the time element which is present is consistent with the Word's existence "in the beginning." The world which came into being through Him, means He was before the world. The life of John the Baptist (cf. Luke 1) shows "He was before me," means the same since John was conceived before Jesus.
The internal aspect or process of action of "was", is essentially speaking about relationship when the subject is the Word. Therefore the force of the imperfect throughout the Prologue is one which the Word is eternal both in time and in relationship with God.
This is made specific at the end of the Prologue:
θεὸν οὐδεὶς ἑώρακεν πώποτε μονογενὴς θεὸς ὁ ὢν εἰς τὸν κόλπον τοῦ πατρὸς ἐκεῖνος ἐξηγήσατο
ὢν is the present participle and ἦν is the imperfect of εἰμί which is to be, to exist.... The Word which was in verse 1 is the μονογενὴς θεὸς ὁ ὢν, the only-begotten God, The One Who Is, in verse 18. That which "was" is "The One Who Is" because He was in the beginning, the Word.
1. Daniel B. Wallace, The Basics of New Testament Syntax, Zondervan, 2000, p. 232-233
2. Fredrick William Danker, A Greek-English Lexicon of the New Testament and Other Early Christian Literature, The University Chicago Press, 2000, p. 495
3. "Here the article with both ζωη — zōē and πως — phōs makes them interchangeable." Robinson's Word Pictures of the New Testament The life was the light of men and the light was the life of men are both possible.
4. Wallace, pp. 247-248
5. M. E. Boismard, O.P. St. John's Prologue, translated by Carisbrooke Dominicans, Newman Press, 1957, p. 80
6. Ibid., p. 79.
7. Loc. cit.