That certainly NRVER stopped Me I only have three. an early 645, 1 of the first 100 4506, marked 645 on the frame, and a N.I.B. 4506 no dash with adjustable sights....How could you not?
I tried it, didnt work, Fits O.k. but there is some type of firing pin block, not being de-activated, I have held the 39 slide and the 439 slide, side by side, and I am just not seeing the difference....
I HAVE PURCHASED A FEW OF THESE TRADE INS, TRY TO FIND A NICE ONE. AND ENJOY I HAVE NEVER HAD A PROBLEM, THEY JUST KEEP BLASING AWAY..I THINK ALL 3RD GEN PISTOLS WERE WAY OVER ENG.
Not common, I collect these and have never seen one, my guess is someone. beadblasted the frame and coated it. as the anodizing was very easy to chip, or wear off.