RickB said:
...S&W 539... was succeeded by the . . . 3906(?), but there were lots of variations...
Here's a rundown of the S&W 9mm single-stacks.
1st-generation: Wood screw-on grip panels, 8rd mag, separate barrel bushing, LH-side decocker/safety, integral front sight, blade-style rear sight that adjusts for windage only, no trigger-actuated firing pin block. All models have steel slides.
- 39 no-dash: Steel frame, blue or nickel finish, uncommon and sought after.
- 39-2: Alloy frame, blue or nickel finish, far more common and generally cheaper than no-dash.
2nd-generation: RH-side ambidextrous decocker/safety initially optional and later standard, trigger-actuated firing-pin block added, rear sight changed to standard drift-adjustable blade or optional (and big!) fully windage-and-elevation screw-adjustable unit, various internal improvements. Otherwise similar to 1st-gen.
- 439: Alloy frame, steel slide, blue or nickel finish, far more common and generally cheaper than 539.
- 539: Steel frame and slide, blue or nickel finish. Only offered for 3 years IIRC; few sold.
- 639: Stainless steel frame and slide.
3rd-generation: Grip changed to one-piece wraparound matte black plastic. Various internal and external improvements including beveled mag well, integral barrel bushing, coned barrel. Compact and subcompact models introduced. Ambidextrous safety lever generally standard, although omitted on "Value Series" and a few compact models. Front sight mounted in dovetail. Fixed rear sight initially blade-style, but changed to slanted Novak-style in 1992, and adjustable unit still offered on full-size models (the three types do NOT interchange unless the entire slide is swapped over). 9rd mags introduced on full-size models late in model run.
- 3904: Full-size, black alloy frame, matte blue steel slide. Only produced for 3 years.
- 3906: Full-size, stainless steel frame and slide. Only produced for 3 years.
- 3913: Compact, silver color alloy frame, stainless slide.
- 3914: Compact, black alloy frame, matte blue steel slide.
- 3953: DAO 3913.
- 3954: DAO 3914.
- CS9 "Chief's Special": Subcompact version of 3913/3914; blue and SS versions offered.
- 908: "Value Series" lower-priced version of 3914 with less refined slide machining, various plastic parts, and no RH-side decocker/safety.
- 908S: "Value Series" 3913.
- 909: "Value Series" 3904, only produced for 1 year.
- 952: Pricey and highly accurized Performance Center SAO pistol roughly based on 3906 but with earlier-style grip panels; blue finish offered on some versions.
The 3913 and 3914 were also offered in a LadySmith or "LS" version with a slant-cut frame, light grey grip unit on 3913, "LadySmith" frame script, and a cute purple gun rug; there was also a "NL" version, which was basically the LadySmith without the last two features, for buyers who felt their masculinity was threatened.
The 3913 and 3953 were offered in a "Tactical" or "TSW" version with a black hammer, trigger, and slide stop; additional slide and frame machining; an accessory rail; and a big and butch (or gauche, depending on your taste)
TACTICAL slide legend.