Black interior was available with every exterior color, it was the interior colors other than black that had restrictions.

Nice car by the way.

Back in '68 when I was in grade 1 I used to ride a school bus past a house that had what I thought was a '68 Impala Super Sport. The car was actually just an Impala Custom coupe that had been repainted (as a new car)in a metallic orange and had 1965-66 Super Sport nameplates on the front fenders. For a couple of years I thought that was how the Super Sport was in '68, that is until a proper Z03 Impala Sport Coupe showed up in the school's parking lot with the proper grille, fender & trunk emblems & the unique interior. I didn't even know about the unique SS-427 until around 1980.