Whether sensus plenior (either inspired or not) exists is largely a question that depends on the particular doctrine an interpretation is evaluated in. Certainly the early Christian writers believed that the Hebrew Scriptures they inherited contained important links with the man they had come to revere as the Messiah. There's no particular reason why they wouldn't continue to use all the tools of interpretationall the tools of interpretation available in the culture they were active in.
Among the Dead Sea Scrolls, we find examples of an interpretative technique call PesherPesher, which re-interpreted the Tanakh in light of current events. There's no particular reason to suppose that early Christian authors, most of whom were Jews, would not try their hand at the same technique. In fact, we know that Jesus himself interpreted the prophesy in Daniel 7 as a being fulfilled in himself. So it's no particular surprise that his followers would not discover hints of Jesus' life in the Tanakh as well.
Conclusion
God only knows whether or not any particular interpretation is inspired. Certainly the authors of the New Testament believed they were discovering deeper meaning in Scripture. However, there's no particular need for us to follow their precise techniques since those methods are not commonly used in our culture.