I was shocked myself when I saw that early this morning because I've been researching Miyata's a little bit lately. Even though it's too tall for me I fired off an email, but I've got zero response so far. Looking at the 1984 Miyata brochure I found online I think you may be right about it being a 912. Unfortunately no phone number was given, I imagine it got snapped up pretty quickly yesterday at that price.