The serial 825xxx with no prefix places the gun in the second half of 1941.
By that time, there were hardly any civilian sales. Most M&P’s were produced in .38 S&W for shipment to the British and allies. Revolvers in .38 Special from that particular time are not common. As the plugged lanyard hole on yours shows, it was most likely produced for an agency contract or some other official order too.
The grip panels aren’t original; they’re post-1968 vintage replacements.
welcome01 to the forums from the Wiregrass! In 1941, S&W was furiously producing .38 S&W M&P revolvers for the British Commonwealth. Occasionally, they produced a .38 Special 4 or 6" for the domestic market. They also occasionally produced them for the war effort but these usually have a lot of proof and acceptance stamps on them from the Brits, Canadians, South Africans and Aussies to make them stand out. Since yours lacks those stamps, it likely was a domestic sale or, as Absalom says, was an agency contract. I don't see any sign of a plug in your lanyard hole. So, a new swivel could be fitted along with appropriate grips to restore it to the configuration it shipped in.
It seems about most everything from about 685000 onward got the butt swivel treatment. That translates to May 1940. Of course most everything was going to the British war effort from that summer onward until we began ramping up.
Pkpkay, could you post a couple of close-ups of the sights of your old S&W revolver. Do you know who did the work or was it done when you got the gun. I've got a 32-20 that I've thought about giving the same treatment to. I would have to start with one with a better barrel than my old one. Really like the old gun. Soak it, flush it out. Oil it up and shoot it, if it breaks then put it in a shadow box.