Be sure it is a GTO and not a le mans. A guy I know bought a "GTO" (70 i think) from this old dude and it had all the right badging, and the grill was painted and looked just like a GTO right down to the Interior. After purchase, we ran the block code firewall and vin Numbers, Well the engin was out of 74 fire chicken, and the car was infact a le mans. We scratch back the paint on the bumper and wohlaah, chrome.
Buyer beware!