1976 Eldorado Paint Color
 

I'm working on my White 1976 Eldorado Convertible and keep finding a brown paint color underneath other areas of the body. Data plate says it was originally white but until I find solid evidence it was I'm skeptical.
Can anyone tell me what color primer Cadillac used in 1976 and what part of the body was actually painted?

dark grey, body is dipped floor pan under carpet or undercoat should be original color.

I haven't pulled back any of the carpet. I'll take a look. Thank you.