However, in concours judging (not thoroughbred) isn't it true the part has to look correct but the casting date is ignored? If the part looks different (like single rib instead of double, N case, etc) then it would "look different" and not pass.
Wouldn't the same hold true of the tag? Isn't the tag the same as a part number and as long as it looks like a FoMoCo tag it's accepted?
Hmmm, maybe this should go into the concours forum folder . . .