I do not know when it was refinished, just that it had a Mauser banner toggle train- the other info was supplied by Thor. The receiver Z(?) at the base of the barrel has the 1920 stamp.

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The toggle train is from a Mauser Banner Luger and though the serial numbers appear to match , the font on the 3 and 7 differ from the rest of the gun which appears to be a 1920 Dated Alphabet DWM with the Eagle over As acceptance markingsjust like Figure 38a Weimar Lugers, page 139. Sear safety is in place but rivet is blued. Looks like someone replaced the toggle train from a Mauser Banner.