I found the reference to "Nash Lugs", here's a catalog page:
http://www.framebuilding.com/Lugs%203.htm
seems like PSE (BSE?)is an Italian lugmaker, tho I'm not familiar with them...anybody care to shed some detailed info? And a BSC threaded BB shell is not unknown in an Italian bike of a certain age: Bianchi had switched over to BSC in their steel frames by '99-'00 era. Then they pretty much stopped using steel