I have no idea why, but some guy with a HVAC business out of his home had this vintage Mister Donut sign. I have a feeling that this panel was reused. It looks like his own sign might have been glued on top of it (see the residue on the sign?), and fell off. Yay for that, since I now have a photo of this, a cool old sign.
Oh, and this points at the entrance to his shop, which is another reason I think it was reused.