I think there is a real difference between being tied for a regular season conference championship and being just short of winning your division and and playing in championship game.

I would expect Utah's record books to reflect that they were Co-Division-Champs. The Pac-12 recognizes that, so Utah should, too. I don't think I would put up a banner. If you aren't playing in the Conference Championship Game, you didn't "win" your division. Co-Champs or not.