deciphering my new 65 Barracuda

Interesting you bring up dark blue "primer".

I have an original paint 67 Belvedere station wagon.
It is white with a 2 tone blue interior.

The paint is very faded in places and in some, specifically the doors and the tailgate, you can clearly see there is dark blue under the white.

I understand the implications of the blue interior, but why would blue be at least half way down the sides of the doors and tailgate, on the outside?

I repeat, this is an original paint car.