On the Prewar K-32 question:
Seems to me I have heard of .32-20 targets that were provided with a separate .32 Long cylinder, and I would imagine that .38 M&P Targets could be converted to .32 Long Targets with a couple of fairly simple parts replacements if an order came in while there were a bunch of unsold .38 targets in the vault. I think I would leave the .32-20s out of the K-32 Target classification, and I am not sure what I would do if we found a .38 that was rebuilt as a .32 before leaving the factory. I suspect if it happened in the 1930s, I would group it with the few dozen unquestioned K-32 Targets manufactured late in that decade.
But in some respects I'm still not sure we all agree on what we are including under the heading of "K-32 First Model." In HOSW Roy Jinks says the first such gun was 663107, "completed on April 15, 1938." But since then specimens have turned up with lower serial numbers or earlier shipping dates -- including the one that started this thread, for example, which carries a slightly higher number but shipped in late 1937. Two other guns known to me (one observed, the other known from records) have lower serial numbers but are still above 650000. One of those was shipped in 1936. Are all K-frame .32 targets from the late 1930s to be considered K-32 First Models even if the term was not created by the company until after the first ones were produced? I would argue yes, but I have the sense that not everyone is in agreement.
I am aware of the few K-frame target models produced before and perhaps immediately after WWI in .32 Long, mostly with four inch barrels. I know there is a bit of a simmering discussion over whether these should be considered "K-32 Targets" as the factory used the term in the 1930s. I take no position on that because I am trying to get a grip only the number of .K-frame .32 targets produced between, say, 1935 and 1940, when the military contracts pushed commercial production off of the factory floors.
In Smith & Wesson: 1857-1945, Neal and Jinks identified 83 serial numbers of K-32 First Models. By 10 years later, Jinks reported 94 guns in HOSW, but without a list of serial numbers. The 94 figure has been repeated since, though some additional serial numbers have been reported over the years and a few guns have popped up in forum posts. When reported with serial number, these guns may be "new" guns or guns that appeared on the original list of serial numbers compiled from factory records.
If anybody has serial numbers for observed K-32 First Models between about 650000 and 685000 and would be willing to share them with me for purposes of building a data base, I would very much appreciate hearing about them. At the moment, I have the serial numbers of 17 guns that meet those standards. In one sense, that is not a big number. But as a percentage, that is quite a large quantity for a limited production run. In the cases of other rare guns (production not exceeding 1000 to 1500 units), observed specimens amount to roughly four to six percent of reported production after extended research in forum posts and internet auctions.