Interior trim/paint codes usually are not listed in the color chip charts. Sometimes, they are listed in the factory service manual. I would suspect they'd also be in the "INFO" section of that parts book and in the "Color/Trim" section of the Dealer Order Guide. Sometimes, in some of the color chip charts, the interior paint codes were listed at the end of the exterior paint chips, but with no chips themselves, just a listing of the codes and their names. From what I saw in PPG, this was not consistent with all model years, BUT it might be there on the first year of when the interior trim codes changed from what they'd been previously.
It's possible that the interior colors were not the same exact colors as the similar exterior colors, but "harmonized" instead . . unless it was "white" or "black".
The Hamtramck Registry website has some color/trim items in particular model years, in their "Library" section, I believe.
CBODY67
