When Ertl owned AMT, the kits came with an invitation to subscribe to Blueprinter. If I remember it was a quarterly magazine, had model building tips and sometimes had special offers where you could buy (by Mail) limited production model kits. The kits came in a black and white printed shipping box, but were kits you couldn't usually get otherwise. The promo-style 1964 Galaxie 500 was one of these.