"too thick or doesn't look factory original" can mean a lot of things. again, in the 80's there were changes in finishing. i have a 1984 SF-4, and was recently questioning the finish myself, but it is definitely factory. however, there is a chance it is poly and not nitro. otherwise, it is a different nitro (technique and/or ingredients) than "more vintage." some late 70s Starfire bass owners have reported similar observations.
your guitar is probably original, cant blame elderly for covering their liabilities though. i once bought a JS-2 bass from Rivington w rare Hagstrom pickup configuration. they swore to me the bridge pickup was a mod, and "i don't know where they found those original 2 knobs!!" i told them "this might be all factory" they said "not a chance". ...OK THEN
so the price was normal since they thought it was modded, but it was rivington, so it all evened out. rivington still wins though, as they made the sale (as did elderly)