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We need the serial number from the butt, to get an idea of when your .38 Military & Police Model left the factory. But from what we can see from the single photo, it is probably from the 1911 to 1917 period. The stocks, monogram and extractor rod knob (combined) point that direction. The lack of Made in U.S.A. on the frame clearly indicates that it is from before the spring of 1922.