Great question! Indeed the verse does not tell us whether the blood actually touched the mercy seat. But in Rabbinical sources we may find the answer to your question.
According to the Babylonian Talmud (Yuma 55a, as explained by Rashi) the blood never touched the mercy seat, it was just sprinkled in the direction of the mercy seat. Similarly the blood need not touch the veil, but if it did there is no harm done. However, in the Palestinian Talmud (ibid 5:4) we find an argument between the Rabbis whether it needs to touch the seat, and according to Zeirah (זעירה) it is a biblical requirement that the blood actually touch the mercy seat.
Keep in mind that though there was no requirement that there should be contact between the blood and the mercy seat/veil, since the priest stood right next to it and sprinkled in it's direction it is reasonable to assume that, in a lot of cases, there was contact between them. Indeed in Yuma (57a) we find testimony of Elazar ben Yosei that he saw that the veil in Rome (after the destruction of the second temple the holy vessels were stored in Rome) and it was full of blood droplets. Apparently some of the droplets landed on the veil. By the same token we can sensibly assume that there was contact between the blood and the mercy seat as well (unfortunately we have no testimony since there was no Ark of covenant since the destruction of the first temple).