Jimbo,
Welcome to the forum. And bravo! No one could say that you didn't do your homework!
Tonight is the first and last lesson with regard to S&Ws:
"THE MAIN RULE IS, THERE ARE NO RULES!"
The more we learn about them, the more we find anomalies that don't fit the facts. In other words exceptions abound.
You experienced one of them, the miss-stamping of dash #s. We also see miss-stamping of the Model # itself but not near as often.
I have one exactly like the one you saw. Always go by the serial # and the one on the butt. That's not to say they haven't been mis-stamped as well, but that's much more rare.
With as many as I've seen, the Model 34-1 had a particular problem leaving off the -1. I believe it's more then a simple miss-stamping, usually a 'one off' problem.
I suspect it was a multiple miss-stamping issue, perhaps a whole days production or more, maybe a Monday or Friday. Either the "Mod 34-1" stamping die was miss-aligned in whatever jig was used to stamp the frames, or the -1 broke off the die and no one noticed, etc. Because although there's enough room in the yoke for the full stamp, it's just positioned too far back in most cases, which drops the -1 off the rear edge of the yoke.
The problem seems to cluster around the '69-'71 period But that's all I know about it. The serial #s don't matter because I'm sure you've read enough to know that neither S&W's production or shipping corresponds to serial # order.
So as Jack said, the length of the cyl to ID an I or J frame is foolproof, and there's quicker ways to tell at a glance that will help you in your hunt for .22/32s.
COMPARISONS OF KIT GUN FRAMES; PRE WAR I, TRANSITIONAL I, (no 22/32 Kit Gun IMPROVED I Frames were ever made), Model of 1953 NEW I, AND J:
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The I and J frame size is determined by the main frame cylinder window length, not the trigger guard and grip frame length. There's a version of I frames with both the small TG/short GF and also the Model of 1953 new frame version with large TG and long GF.
Also there are two J frames: the (Baby J) with small TG and short GF, and the Model of 1953 New J with large TG and longer GF.
Here are a few pix to help illustrate the differences between the pre war I/post war Transitional I/"Improved I”, from the “New I; and the Baby J” frame from the New "J" frame revolvers:
Top gun shown is a post war .22/32 Kit Gun Transitional I frame, which is also what the .32 and .38/32 Transitional I frame and the Improved I frame (with coil mainspring) look like sans target sights (no Improved I frame .22/32s were ever made). 'Improved I' frames in .32 and .38/32 will have a round sight on the early versions and have a ramped front sight with ribbed barrel on the late versions, pre 1953.
The Transitional I frame Kit Gun has a Pre war sight, leaf spring, and 6 screws. It looks like a 5 screw Improved I frame, the improvement being the coil mainspring. But no 22/32 Kit Guns or Targets were made on the Improved I frame.
Bottom Kit Gun is a Model of 1953 "New I frame" (the true Pre-Model 34), with coil mainspring, micro-click sight, new wide target hammer, ramp front sight, barrel rib, flat latch, and only had 4, and after 1956, 3 screws. It still has the I size main frame cyl window length, but the New I frame forging trigger guard size and the longer round butt grip frame length, 1/8" longer than the pre war, post war transitional I, Improved I, and Baby J frame.
Visibly they can be distinguished as shown below by the curved lower checkering border (note: some of the very early longer I/J grips will also have the curved border), and difference in un-checkered wood length at the butt, (mini Magnas shown in top photo):
(The NEW Model of 1953 sq butt available option for all the New I & J frames, is an additional 5/32” longer than the rd butt - not shown).
Photo credit: BlackAgnes
This photo below, compares a post war "Transitional" I frame Kit Gun with pre-war features, such as a leaf mainspring, no barrel rib, and pre-war sights with a Model of 1953 "NEW” I frame below it. The "Transitional" gun was actually shipped a year after the Model of 1953 pictured!
Photo credit: BlackAgnes
Next, this photo is a comparison of a .22/32 Kit Gun "J-Frame" (Model 63 stainless Kit Gun, top), and a Model of 1953 "New I-Frame" (Pre-Model 34/Model 34 22/32 Kit Gun, bottom). Same size trigger guards and grip frames, but note the 1/8” difference in frame length in front of the trigger guard and top strap, also compare the cylinder length and cyl window length. The simple identification "giveaway" of the I frame pre and post 1953 is the cyl square profile from the side view.
Photo credit: BlackAgnes
A similar comparison of a .22/32 Kit Gun "J-Frame" (Nickel Model 34-1 Kit Gun, top), and a Model of 1953 "New I-Frame" (Pre-Model 34/Model 34 22/32 Kit Gun, bottom)
Photo credit: JP@AK
Here are a pair of Kit Guns both Model of 1953 NEW I frames, top is a three-screw and the lower is the earlier four-screw, the top or 4th screw being deleted in early 1956 - they are otherwise identical except for barrel length. There was also a choice of round butt Magna grip frame or square butt Magna grip frame.
Photo credit: BlackAgnes