If it was stolen before I sort of understand him being cagey, I've had my FD RX-7 stolen before. In fact when I went to look at it in Ireland, we met at a mutual location in a shopping center car park. If this car is registered, he should be able to drive it to meet you somewhere mutual if he's worried about people knowing where it's stored etc..
I would say that yes 240z's are rare, but they are also notorious for rust and you want to inspect it closely to see how much work the body needs before bidding because that's where all the value in these cars is..