Before shelling out the $$$ for anything Phil, I'd make sure. Every Moto I've worked on has been Swiss threaded (Same pitch and sizing as French, but the fixed cup is reverse threaded). Swiss cups are extremely hard to find. If yours are in good shape, keep them, don't replace them. Overhaul with fresh grease and new bearings.

I have heard reports you can get English cups into Swiss frames, either by forcing or retapping, including reports from at least two folks I trust, but I have not verified this myself. Keep meaning to retap and see, there's about 3 Swiss threaded frames in the basement and a set of taps in the tool box. Keep getting distracted by other stuff. You can also get a YST bb for spent BB threads, about 20$ from Biketoolsetc.com. Should work okay.