S&W completed the first Combat Magnum on December 15, 1955. The next three or four were completed in January 1956. S&W only made 77 Combat Magnums through the end of April 1956 as production really did not ramp up until May. Based on the fact S&W used stocks on the 44 Magnum with the relieved area, I believe they also chose to use the same type of stocks on their new Combat Magnum. That is not to say a few weren't shipped with the earlier style of stock, but I know some guns have had their stocks changed due to the AMC that first listed the Combat Magnum (photo posted above) because the owner thought the earlier style was correct for their particular revolver.

Bill