I uncoverd a set last year on a 69 COPO Camaro I restored. The drive shaft had been covered in some kind of black Yuk. I could see the outline of two stripes and carfully wet sanded w/600 paper. They were very thin, but I was able to atleast determine the colors for later re application.
Let us know what color you find and the car type.
This is what I found, 4 speed L72 COPO Camaro.
Good Luck
Mike