Hiya Harry,
Are your window stickers repops? I'm guessing that they are, given the great shape they're in.
I've only seen Oregon referred to as the "Sunset State" a couple of times. And those are pretty early references. Late forties, early fifties. That went outta the window with the admission of Hawaii as a state. Even prior to the sixties Oregon was better known as the "Beaver State" (yeah, I know; but whaddyagonna do?). Stickers appropriate for the age of your Bus (Wow! Nice Bus.) would be of the "Beaver State" vintage.