My friend was redoing brakes on a C3 Corvette and found when rebuilding calipers with O ring pistons yhat one caliper had smaller piston bores. Corvette supplier told him they were probably from a Camaro with rear disc brakes because of bore. Casting #'s are 5473807 and 5473806 on split caliper. Also has a 2 and 6 on caliper. Anybody know what this fits or if it is Camaro?