Enlarging the photo doesn't help much, but it doesn't appear to have the narrow slide plate to the front of the machine like a model 13 does, so I'd agree that it's a New Family 12....if I understand the research correctly, made from the 1860's to the 80's...(don't quote me on that!)
It is a straight stitch, transverse shuttle machine. (I'll post a link) It takes a boat shuttle, and if I'm not mistaken an odd needle.
http://en.wikipedia.org/wiki/Vibrating_shuttle
GO GET IT!
