I think you'll find the "buffed silver metallic" is a middle-of-the-road color on the '68 GTX, not the most popular & not among the rarest.

& since all 8 available interior colors would go with the AA1 exterior paint (not quite sure about the black & gold) - that would enhance the uniqueness of each color combination. Moparts member cdp has a '68 GTX convertible that is AA1 with the S6V interior, there shouild be some pics of it somewhere. Got pics of your car?

Lots of reading & info at HAMTRAMCK-HISTORICAL

& since one of the ad cars were AA1 and S6R, I'd bet there are quite a few in that color combination!!!