Excellent gun and fairly old. It's not a rare gun as these were used by many PD's back in the time. What probably makes it rare is that it looks to have seen very little use.
I beg to differ, and the devil is in the details. It’s important because it can affect the value.
World War Two ended on September 2, 1945 when a Japanese delegation singed a formal surrender document. Smith & Wesson had suspended production of the military version of they’re pre-war .38 Military & Police (1905 Hand Ejector, 4th Chg.) revolver on August 26, 1945 in anticipation of the forthcoming end of the war. As the Victory Model passed into history they moved into a new factory in Springfield, MA. And looked forward to resuming commercial production, as the pent-up demand far exceeded their ability to meet it in the short term.
Production of new law enforcement/civilian Military & Police revolvers began on September 12, 1945 using a new “S” letter pre-fix in the serial number to denote the addition of a new hammer block that made it safe to carry the revolver with all six chambers loaded. The number itself (811,120) started where the Victory Model (SV 811,119) had left off.
The first revolvers were made using parts left over from previous pre-war and wartime production (mostly the latter), but besides the hammer block safety and polished blue or nickel plated finish, the most obvious change was new “maga” style checkered walnut stocks that had a horn-shape at the top that better supported the web of the hand and distributed the recoil. These stocks had been designed before the war, but hardly introduced before they were discontinued as wartime production took over.
Also before the war, S&W had designed a new, substantially different action that made it possible to cock the hammer while rotating it over a shorter radius. This appealed to those shooters who would habitually cock the hammer with their thumb, rather then fire by simply pulling the trigger in the double-action mode. However there is no such thing as a free lunch, and in this case the double-action trigger pull was slightly degraded over that of the previous system, which was now called the “long action” while the new one was designated to be the “short action”.
Again, the newer short-action was hardly introduced in other models, when it was dropped by the onset of the war. Following the war the company planned to introduce it across their entire product line, but for the time being continued to make the .38 Military and Police revolver (called “pre-model 10” by collectors) using the older long-action. Those .38 M&P revolvers that were made using surplus wartime and pre-war parts were called “transitional” models.
Because these revolvers had what some claim to be the best double-action trigger pull ever offered in a production revolvers, along with a hammer block which made them safe to carry fully loaded, and incorporated none of the cost-cutting changes that would come about in the future; these revolvers became popular with both knowledgeable shooters and collectors as time went by.
Within the commercial K-frame product line, the above features were only available on transitional M&P revolvers, and production was limited to parts-on-hand.
The revolver that is the subject of this thread is an excellent example of a late production transitional .38 Military & Police model. Given what it is, and the almost-like-new condition it is in, I would estimate the value to be in the $600 range, and going up.
Because most of the long-action/transitional revolvers were sold to the law-enforcement market, and then used to the point of destruction, an example in the condition this one is in should indeed be considered to be scarce to rare.