I think your color match is good too....and I'm sure anyone CAN get them FREE from GM by talking to the right people...like you did!
Some might be picky on the exact color or if the word "cinch" is white or orange (I'd change that color easily myself too...some wont oddly enough as simple as that is!).
As for GM putting parts aside....they certainly did for a period of time...but think about the logistics and expense involved. They made X number of belts and after 20+ years people still hadnt used them with the recall. Odds are most of those cars under recall were junked or the belts worked OK. The parts are sitting somewhere and a paying customer wants a new set...I'd sell 'em too!
Now 25 years later people whose belts did work OK for years want new ones because theirs are dirty and dingy?
The aftermarket will make them eventually anyway. GM can get them from there eventually if need be....