Rich,
On your 68 where was it built, what is the second digit of the VIN #?
F-Dearborn, MI
R-San Jose, Ca
T-Metuchen, NJ
Your VIN plate should be rivited to the dash on the l/s visible through the front windsheld, & if the car was built in NJ it probably has a body buck tag screwedeither to the top of the inner fender panel, or to the radiator support. My 69 Coupe has one screwed to the top of the inner fender panel by the r/s hood hinge like Julie describes, & my wifes 65 Fastback has one on the radiator support. The VIN # should also be stamped into the top of the front inner fender panels, one will be visible & the other will be hidden by the fender on the other side.
Mike.