David, I checked a few listings for what Ford called "Folding Top Compartment Trim". The Torino and Mustang applications only show black and my Cougar info shows the same. Like Luxstang posted I feel the white would cause some terrible reflections in the rear glass.
The Ford part number is D1ZZ-7654602-A and the engineering number is D1ZB-7654602-AOO1A. There may be some suffix variations on some later 73 liners but most will be be like I posted. If you do find a number on the white one that appears to be Ford formatted please send it to me so I can see what it is!