update: the bottom bracket is either French or Italian. I attempted to thread a GXP English bottom bracket in there and cup marked "right" went in fine... into the left side of the bottom bracket shell. and it went in way too easily, as if the cup is just a tiny bit too big. the left cup would not go in properly on either side at all, so I didn't force it. I will have to consult the lockring knurling orientation to figure it out.

unfortunately, this is the end of the line for me. I wanted to make a practical bike for riding to work and long leisurely rides, but I don't want to deal with oddball stuff like this. It's already been claimed by a local i know who loves to refurb vintage stuff, so sorry.