It is a postwar .38 Military & Police square butt revolver. It most likely left the factory in the November - December 1946 time frame.
Most poswar M&P revolvers had the square butt. But the 2" variation was built with either the round or square grip frame. I don't show any other 2" guns in my database that are near this serial number. It would be a big help to my research if you could send me the complete serial number. Use a PM if you don't want to show it publicly.
S868055, identical to yours, shipped in January 1947. I would agree that a late 1946 ship date for yours is likely -- but because of the way S&W handled shipments, there is a chance it might not have left the factory until 1947.