It might be easier to go through the color list of what hasent been seen.
The past few years has brought out many of what some would consider the less desirable RR-RT cars, odd color options and bench seats but the FT dont lie.
I wasn’t able to find much on the available colors for ’76 Road Runner’s.
I did find this, published in ’77. It is a Color and Trim book that dealers had access to, for those picky buyers.
A copy of the front cover, page # 16 and a blowup on page 16: