DECREASING SERIAL # LOCATIONS:
The number of serial # locations or if a Model/dash # is stamped on a particular S&W Hand Ejector has more to do with where it was in the production/assembly stages then when change orders were issued, therefore as we've learned to expect with S&W, there are great variances and exceptions galore.
Officially, on May 3, 1957 S&W eliminated the Soft Fitting Operation: So it generally corresponds with the model number designation stamping, change order June 12, 1957 but didn’t take affect for many months. It was no longer necessary to routinely stamp the serial number on the barrel, cylinder & yoke arm rear surface and serial #s still exist at those locations or not, over a transition period. So guns in process or in inventory as of 5/3/57 can still have more than 3 and up to 6 serial # locations, and guns shipped after this time may have some of the former number locations because assembly was done over time and as inventory from the old process was used up.
The 6 serial # locations were down to only 3 left on the majority of models (but not all) from c. late 1957 to 1959 which are:
1. Grip frame butt (K & N frames prefixed by a letter(s) following WWII)
2. Extractor star - backside
3. Right stock – backside (except most post war target grips because individual fitting not required.)
FRAME YOKE CUT STAMPING of the assembly (work) # vs. serial #:
changes after Model # stamping got more confusing. When Model Number stamping began some months to a year after being ordered June 12, 1957, the serial number was not yet stamped in the frame ‘yoke cut’ on the frame side of the yoke hinge. But in the l958-1959 time period as the use of target grips became more common and if the revolver was ordered with or was standard with target stocks which covered the butt serial #, the serial number is stamped in the yoke cut of the frame. The assembly number would have also been in this area, as it was stamped on the gun long before the revolver was serial numbered.
But when the serial # was stamped on the frame in the 'yoke cut', except on the smaller frames at first where it just didn't fit well, the frame assembly # from the 'yoke cut' was moved to the left side of the grip frame. The 3 assembly # locations became the yoke, left side of grip frame (later the right side), and backside of side plate. However, the post 1959-60 yoke cut serial # placement on the later guns is the reason for many pre 1957 guns to be incorrectly registered by the useless assembly # on the frame in the yoke cut.
Therefore by about the end of 1959, serial # locations went up to 4:
1. Grip frame butt (K & N frames prefixed by a letter(s) following WWII)
2. Frame in yoke cut
3. Extractor star until ~ 1980 when the new extractor star shape was introduced.
4. Back of right stock, until ~ 1979 when no longer hand fitted, (except most post war target grips because individual fitting not required).
Note: due to parts inventory, late-built-guns-for-their-serial #, etc., we see many anomalies of cyls and barrels still serial #d well into the early 1960s. Revolvers that were reworked during manufacture (not returned after shipment for repair or refinish) will often have the serial number stamped on the rear surface of the cylinder and rarely on the barrel. Reworking happened quite often from what I have observed for the Model 29. These guns often have a lightly stamped R on the left side of the grip frame (no date):
