77, 78, and 79 coupes are the only Cadillacs available in that style.
each year they had 4 different colored promos
I think each year they also had a kit version, which was basically a unassembled promo with plastic pegs to connect the body instead of metal screws. Kits were usually red, but I've gotten a few in white or peach colored.
Ebay's a good place, a good deal is in the low $20s