The VIN can be found on the inner fender of '65-'68 Mustangs. One exception is San Jose-built '68 Mustangs, where the inner-fender VIN (also known as the confidential VIN) is hidden. This number must match in all locations on the vehicle, including inner fenders, windshield tag ('68-up), and warranty plate or certification sticker on the left-hand door. We've all run into Mustangs with left-hand doors that have been replaced with a door from another vehicle, meaning it has the incorrect warranty plate. In those instances, we suggest removing the warranty plate or certification sticker and using the inner fenders and windshield tag.