As caught by an alert Joshua Henschke on twitter, the latest MDen catalog strongly implies that Michigan will wear alternate uniforms for the Penn State game:
I'm not surprised, I guess. I had just forgotten about the possibility of such a thing and was disappointed to remember we do this now.
I'm sure this will be sold as a throwback to some fictional time in the past when Michigan wore stripey numbers under coach Pterodactyl The Second and won the Big Ten thanks to their velociraptor riders, because Authenticity™.
UPDATE: actually looks like an MGoUser was first to wonder.