those are gm wheels yes, were optioanlly available form factory, any aluminum or steel wheels that accept gm rally caps are factory optional, you would be surprised to see how many different oens GM made available over the years, including steel wagons and so forth, steel wagons started in 73-75 years for the ralely caps that had screws from backside of wheels, and aluminum fins started ont he 69-72 blazers with eagle and feathers and other packages