Old log books
I've lost count now of how many log books I've found for folks in my area. They start flying 20-30 years and give it away, then make a comeback. RAA offers them another choice today. For some, I know where many books are held from an old School and can rummage through them. I make it the students role to maintain their book's possession, I simply vet the entries until they are on their own. Last one went back to the UK would you believe.
Try and find someone from that era who might know how/where to look for you.