Tim in years 65 and 64 its not real easy to tell a cloned GTO froma real one. The only real definitive way is thru the Pontiac Historical society
[
www.phs-online.com]
They do checks on vin numbers for you but at a price if you need quick its $45 or thru mail $35 but its worth it so you dont buy something your not expecting..
Good luck
Eric