I first owned a S&W Model 39 back in the -1970s, and fell in love with it. However, I was tricked into selling it in order to leave Panama (where I acquired it) to go to Germany, "supposedly" because I had bought it from a friend and not through a Rod & Gun Club! It took over 16 years to find another one! The one I did find was the second generation "439". I was never happy with the OEM adjustable rear sights. Finally (and recently), I contacted S&W to ask if the sights could be replaced with the "lollipop" rear sights that my Model 39 had. I was informed that to do so would mean replacing the Model 439 slide with a Model 39 slide. I did so and am completely happy now. I served as a military advisor in Venezuela, and was issued the Belgium Browning Hi-Power 9mm pistol. The S&W Model 39 and its second generation 439 are the closest I have ever found to John Moses Browing's Hi-Power. You have a great firearm that other would want to pick up if you auctioned it off. I do not intend to ever again let go of my Model 439 with the 39 slide and sights.