Thanks, Kevin - that was/is my belief, too.
Nonetheless, painting the letters provides a nice appearance/contrast.
Dealerships which had body shops on site would paint the letters for customers who wanted it done. I was told that was why their parts departments had the adhesive masks on hand. The last time I bought one was around 1978 and I think I paid either $6 or $8. It was packed between two pieces of cardboard and folded in the middle. The package was blue/tan. Couldn't tell you why I remember that, but I do. I never saw a single one which was painted anything but that ivory (whitish) color used for the pin stripe, however. Wish they still had these. They worked like a charm.
