the cutouts in the BB shell are very similar to some favored by Giovanni Losa, but since it's a cast shell there may be nothing to that except an homage...we've seen that same "W" or "M" on the 'webbing' before but don't recall if it was ever ID'd.

Not that it makes a diff with a frame of this vintage, since very unlikely that it's IT threading, but: what's the threading (marking on the cups)?