Here is a portion of the Man of War article: “A third category of reworked M1917 revolvers are those returned to Springfield Armory. …the author has concluded that those handled by Springfield Armory can be positively identified. Consider the following evidence: A sizable group of revolvers exists with one or more sets of numbers in addition to the serial and butt numbers. Those observed usually have a professional-appearing blue-black finish and show signs of a light and carefull polish. Notably, the lettering and some of the tool mark patterns remain, while the Rampant Colt has usually disappeared. As with the “AA” reworked revolvers, the finish was evidently applied directly over the case-hardened parts. If the Colt factory was contracted to work on these revolvers, it is reasonable to expect that they would restamp the Rampant Colt as they did on the commercially refinished revolver described earlier. The firm has always been keen with regard to advertising.
The revolvers under consideration are stamped with an additional two-, three-, four-, or five-digit number. Four-digit numbers are most commonly reported: “1000” through “9999” represent the statistically largest series. This number is located in the crane recess, on the inside surface of the crane, on the rear of the cylinder(under the extractor), and on the bottom of the barrel. When it has been possible to disassemble the revolvers, the number was further found on the hammer, trigger, and ejector rod, although it does not appear inside the sideplate where the serial number was placed during original production. From this discussion, the reader can conjecture that such M1917’s are the ones returned to Springfield Armory, even though they bear no “SA” stamp. Compelling support is provided by the Springfield Armory document stating a requirement for small steel number stamps for the repair process because “…Revolvers are not interchangeable and parts must be stamped when disassembled…”(Pate, p. 68)”