I can positively say the grayish color of mine is one of the correct colors. I've had the car since '69 and I know of another one owner '68 that is that same gray. I say "one" of the colors because I have heard similar discussions which surface more than gray. I believe there is more than one correct color.

Besides mine on the web site, here's one from a one owner POCI Concours perfect score '68: