Be sure the BODY doesn't leak, that the leak the owner disclosed was properly repaired, and it's still holding.
Suggest finding an RV shop/dealer who can pressure test it in the presence of Seller and Buyer. Should cost $100-150.
I'm not a skilled negotiator, but you might want to do your price dickering before testing. Look it all over first, drive it, get questions enswered, but here's my thinking... If it does leak, you can walk away or try to bargain down. If it doesn't leak, seller won't want to come down or come down any farther.
Compare Chassis Year with Coach Model Year. If it's a "1993 coach" then chassis could be '93 but likely '92. 1992 was the first of the body style we see today. The rounded look. Ford had already gone to EFI. I thought that was '89 but some here say '88. I think (not positive) the Overdrive came when they changed the body style ('92 chassis year) and it was called E4OD. Then at some point the 460 went from EFI (throttle body) to Multiport Injection (8 injectors MPI) through 1996 when they (sob...) built the last of them.
I think you'd get good technology out of a 1992-93 chassis. Just be sure it's got a solid "house" on it.