I'm really happy you found a specific revolver outfitted with the a particular hammer style that you've been seeking. I have two Combat Masterpieces earlier than yours, but both have what back in the day were refererred to as having 'beaver tail' hammer, at least in the far southwest of Arizona, near the Mexican border. The first is my dad's service weapon, which according to the S&W letter was delivered to the George Cake Company, Berkeley, CA, November, 17, 1953. There was no mention as to the hammer or trigger configuration. This gun resides in my son's safe as it was a gift to him from my father shortly before he died. It's one of my son's most valuable and protected treasures.
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This one is mine, found in a Prescott Valley, AZ swap meet. Sadly, the condition today doesn't match this picture due to a storage tragedy, of which I learned a very painful lesson, but sadly the event damaged several of my handguns. No matter, I lost a safe queen, but gained a crazy accurate shooter! According to the S&W letter, it was shipped to the Hoffman Hardware Co, Los Angeles, CA, June 28, 1950. Again, no mention of the hammer or trigger configurations, simply a blued, 4", with walnut grips (not stocks!).
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As to my dad's 1953 version, old timers on this and the other Smith & Wesson forum years past have told me that it was common for trigger/hammer upgrades to be performed on guns post delivery. I know nothing of the history of my swap meet gun, but I know my dad never had his gun 'upgraded' and he seriously doubts the old Yuma County Deputy that lived in our town, the man that sold it to my dad for $50 bucks, which was a lot of money in 1955, he never said anything about an upgrade, and it's unlikely he had any reason to do so.
To me, this is the hammer I'm used to from the old, original Combat Masterpieces. I also have a Model 15-2 and a Model 15-3 snub, they have a more modern hammer, but they shoot just as accurately as the older versions. Full disclosure, I rarely engage the hammer at all, I primarily shoot in double action mode, so to me, it's all about aesthetics. Again, congrats on your find and keep up your collections search!