Norwood paint applications

[raw muscle cars]

I recently bought an old 70 camaro drag car. After stripping the car to its shell, I have noticed the whole car inside and out is primer red, then black wich is flakey ,then the colores of the car. My question did gm paint all 70 cars primer red and if the car was stripped of old paint at one time would that not also come off?

thanks richard