I just got done try to fit a pair of Scott Drake 67-68 Fastback Interior Vent Grills to the interior panels on a friends 67 Fastback. The key word is try. With a lot of elongated holes on the fiberglass panels, we managed to get somewhat of a good fit. A side by side comparison, with a little measuring, show the replacements two front mounting studs to be about 3/16 of an inch too short. Hence the elongation of the rear 6 holes to fit.The original grills are pot metal, the replacements are plastic. This is just a word of caution.They look good, but it's more than a simple replacement.
Jim