I suspect that the correct serial number is 877,607. After S&W reached serial number 999,999 in early 1942 they changed to a "V" series, starting at V-1 in 1942 and going to somewhere in the V-700,000 range on 38-200 revolvers by 1945.
I would expect a revolver made during this period (late 1941)to have British proof marks on the cylinder, frame and barrel, and it would be almost impossible to remove all of them without being obvious. Since you have made no mention of them I conclude that is was likely diverted and used to arm U.S. Defense Plant guards or our domestic police forces. This was not an uncommon practice at the time because there was an extreme shortage of available revolvers for use on the home front. You might take a chance and order an historical letter from S&W and see what you get.
To do so you will need a (hardcopy) snapshot of the gun, a full description including the serial number on the butt, (or in your case the stock) and a check in the amount of $30.00 made out to Smith & Wesson. In exchange the company's historian, Roy G. Jinks, will research the original records (which are not computerized by the way) and send you a letter containing the details of what he finds.
This comprehensive document will contain an overview of the model’s history, followed by the details of your particular gun. This usually includes the caliber, barrel length, finish, and the exact date it was shipped from the factory, and to what distributor, dealer or military authority. If there are any special features they will be listed too.
Additional information on a historical letter will be found at the Smith & Wesson company website at:
http://www.smith-wesson.com/webapp/...catalogId=11101&content=25301§ionId=10504
On the other hand...
If the serial number was V-877,607 that whould make the production date sometime in early 1945, as they ended production at approximately serial number SV-811,000. Your serial number is "out of range," but I've known of that to happen before. Some of the late production guns were shipped to the O.S.S. and lacked usual markings. If it is a late production gun I would expect it to have a positive hammer-block safety. You can tell becaue there will be a notch cut in the hammer face under the firing pin.
Last but not least, it is quite possible the stocks came from another gun, in which case all of this speculation is moot.