I bought my 83 from him. He a little wierd, but okay. As mentioned above, make sure everything is clear between you and him, and make sure to remind him about what he's including (if anything) in the sale. Don't assume anything.
My personal opinion is that he is a little shady but okay to deal with.
1975 Chevy K20 8400lb GVW Camper Special
1971 Gladiator J2000 Platform-Stake Dump 350/T18
1970 Gladiator J3000 3407Z Camper Truck 350/T18
1963 Gladiator J300 Townside 350/TH400