In the 80s in CA, our neighbors came home with a sheltie puppy. They were a bit disappointed - they had been on the wait list, and the breeder was very disappointed with their pup - oversized and a color that wasn't wanted. Now, I know it sounds nutty, but I am pretty sure that sheltie was black and tan. I always assumed that was a normal sheltie color, until we got our own a few years ago, and I didn't see it listed in any of the books.
She was mostly black, with tan eyebrows and muzzle - sort of like a tri but with black replacing the white. I thought maybe I had remembered her incorrectly, but I checked with my mom and my sisters, and the sheltie had no white on her that they remember either. We petsit her often, so we knew her pretty well - she was our first exposure to the breed. (She was a love, but a walking tangled ball of hair.)
So, this post is interesting - I would guess she would have been registered, since our neighbors had to be on a waitlist and her breeder at least knew about the correct sizes and colors, but who knows, and maybe she wasn't registered at all, or registered as a tri? Or, of course, maybe she wasn't fully purebred at all...