Cowl Tag Question

[KNAPPY]

I purchased this car a few months back, it is in rough shape but was sitting in a shop for 15 years or so. The trim tag decodes to a 67 Camaro L78 Convertible but I am not convinced. Most of the original parts are long gone. The build date is very early. I thought L78 Camaros were not introduced until later. I will post some more pictures tonight. I want someone to convince me it is not fake.