Factory Primer: Red Oxide and Black, anybody work at a GM assy plant circa 60's/70's?

[lakeroadster]

Have you noticed that the factory seems to have painted the hood and dog house with black primer, and the rest of our trucks with red oxide?

I am kind of fixated on patina here lately.... and this seems to be a reoccuring observance of mine.

Do we have anybody on this site that actually worked at a GM truck assembly plant back in the 60's and early 70's?

Maybe these photos will get you guys doin the too.