Cadillac Studio showcased their fiberglass design model of the '57 Brougham production car at the Design Dome for a management review on March 17, 1955. At that time, the '55 Eldorado Brougham was still touring the auto show circuit. Subsequently, upon GM management's approval, the 1957 car entered production. It is worth noting that there were disparities observed between the fiberglass model and the final production car.