My '67 came from Campbell Chevrolet in Centralia, WA. Sadly, the original owner's widow had thrown out all the paperwork on the truck when I bought it. It still has the dealer sticker below the tailgate.
My father's 71 CustomCamper/20 was bought brand new by my grandfather in 1972 as a dealer leftover. He still has all the documentation for it right down to the window sticker.
It was from a dealer in East Olympia, I don't recall the name.