Taking the thread back in the general direction of the original posting, along with age and the amount of work/use the bass has had, one primary issue to factor in has to be the material used on the instrument when it was manufactured.
Consider Fender (as this is generally the benchmark for wear'n'tear); they stopped using nitrocellulose on their guitars in the late 1960s...this finish was soft/prone to drying out/crackling/peeling and reacted with rubber in such a way that the finish would melt after prolonged exposure. (It wasn't uncommon for guitars to be returned to Fender for refinishing.) After nitro was discontinued, Fender moved to a polyurethane finish. Hard/brittle/bombproof.
With this in mind, it's feasible that if you had a two identical Fender basses from 1968-70, both of which were subject to [i]exactly [/i]the same level of daily usage and care over a period of 40+ years, it stands to reason that the nitro-finished model would/should be expected to be in worse condition than the poly finished version. This isn't to say that all poly (or nitro) finishes are identical. A generalization is that it's probably a fair comment to say that a 50 year old Poly finish will look considerably better that a 50 year old nitro one.
In closing, the oldest bass I owned from Fender was a 1979 Precision. Poly. I used that bass for 20+ years. I jammed/gigged with it two or three times a week and it was played daily and it barely had a ding on it. There are guys on here who have 50s/60s basses who I'm sure will be happy to share their opinions and experiences. Everyone has their own experiences and production values differ from manufacturer to manufacturer.
P