Correct - it took me awhile to figure out the threading was Swiss. I originally tried an English threaded cartridge bb that I had on hand with plastic cups and they wouldn't thread in all the way.

The original bb had a cottered crank and spindle but the crank was nasty so it went to the dump. I tried a couple of different spindles with the original cups but they seem to be thin wall like a few of my old French thread have been so there was still too much play in the spindle when the cups were seated all the way. That's when I decided to move to the new IRD cartridge bb - which probably is overkill on this frame.