Thanks, I'll upload a few more photos when I get back home.

Nope, Massachusetts.

I was guessing the early 70s. The date code on the rear derailleur is 1972, but I don't want to date the whole thing off of one component. There's also a pair of digits on the back of the head tube, 72 I think, and a 60-something. I'm not quite sure what those might mean. Other than that, I haven't found any other markings on the frame.

I have a sneaking suspicion that someone long ago crammed a 22.2mm stem into the 22.0mm headtube because I haven't been able to get it off with the usual wd-40 and smack of a mallet.