This thread was resurrected at the perfect time... last week I bought a 439 slide assembly cheaply and nearly complete, to get the ambi safety I wanted for my 39-2. Then I still had most of a blued upper, so this afternoon I bid on and won a 639. The plan is to upgrade the blued slide with some parts I’ve got knocking around and add it to the 639 lower to make a two-tone 639... sort of 1980s Old School. I too love a well thought out Frankengun. (Or is it “Frankensmith?)

Froggie