"Some kind of coat that will come off" yeah right, sounds like typical yellowing of an old board. One thing for sure its not in pristine condition
and the seller is not your typical "fastidious" Harbor owner LOL. Rich may be able to give you an idea on price but I had an old Balsa board I got cheap that I thought was going to make me a ton of money. Found out unless they they were pristine, they were waterlogged junk. I think I made $100 profit. Make him a low offer then see if he come back.