I don't think so. There may have been many 1985 built boats with the same name as yours. However, if it was part1, it should have the number carved on a permanent part of the structure (or at least the screw-holes where the original plate was!!)
You could check on the MARS website, but the problem is registration is not forever any more, so boats will probably be deleted if their owners don't continue to pay.
It's worth speaking to the SSR people. They were very helpful when I bought my boat, also built 1984/5. They knew far more than the then owner, who had virtually no paperwork.