Is there a "rule" to how the vin #'s were stamped on the 68 Muncie for the Z28? JM's book shows one that has a 1 before the vin, I guess to denote Chevrolet? Like 18nxxxxx and Pontiac 28nxxxxx. I talked to a guy rebuilding my trans and he said he hardly ever sees the 1 before the vin #. Is this 1 just on Norwood, Los, 68 Z's, certain production runs or what? Or is it just supposed to be there and sometimes it doesn't get put on?