Is there a letter in front of the serial number on the butt? Any other markings? Caliber? The hammer style indicates pre-1948, may be even pre-WWI. More and better pictures would help
Well, the M&P had the Model 10 identity added to its name a good while back---long after this gun left the mother ship---which was very likely late 1914/early 1915.
With the round butt, at that time it would probably have been called a .38 Model of 1902. And the grips are indeed much newer than the revolver, from around the late 1960s or later. Most original round butt revolvers at that time left the S&W factory with black hard rubber grips.
Collectors have named this as a 38 Military & Police, 3rd Change revolver. It likely shipped in 1913 or 1914. Appears to be in nice condition. This is a round butt revolver and would have had walnut gold medallion service stocks. gunpartscorp.com sell original unfinished stocks for that revolver at a very good price.