Thanks guys... after looking carefully at the old seat frame paint I am pretty sure that the entire truck was blue in and out.
When I got this truck it was a basket case completely apart with the hood stuffed through the windshield opening and the doors laying inside. It was entombed in old brown oxide primer. Under this was a blue paint, then yellow then a lighter primer color.
I had thought it was repainted since but looking more closely much of it was not. What really through me was the bright yellow but now I think that the LA production plant mus have used this as a primer under the blue paint.