Should let Todd answer this, but GTOs were generally an American built car, American engine and all that. I know some Lemans had Chevy drivetrains, not sure if they were built here or not.
The VIN will indicate what plant your car was built in. While 1970 GTOs were built in Oshawa ON (among other plants), I think the 1971 was only built in USA in which case PHS is your best bet. You might want to confirm that thought by decoding the VIN.
