^^^ But someone was hopping that car up (headers) and could have added that washer. Most of the musclecar-era magazine test cars were "rubbed on" before the reviewers got them (and often afterwards of course). Dead-stock assembly-line photos would provide the definitive answer if known-untouched 1-owner cars aren't adequate proof. By the same token, a washer added 50 years ago could be a forgotten alteration, and look original now.
