Only thing I could say is if it is from 1967 and has only flown 1620 hours, and the first 500 were from a flight school that owned it - do some math here Steven....

a 38 year old airplane with 1620 hours has been flown what - 43 hours a year average? It's been sitting a lot.

That may be good - but with most airplanes that is bad. Things in aircraft don't like to sit.

I think you'd find a lot of work to be done...even at 620 SMOH, when was that done (calendar time)??