This particular pistol must be divided into three (3) sub-variations. This variation appears to be in a serial number range of its own. First sub-variation appears to run from 1 to 40000. It is highly doubtful if this quantity was manufactured. Second sub-variation incorporates a Zusatzsicherung or Additional Safety which can be seen between the normal safety lever and top of the left grip. It locked the trigger bar when in use. This second range appears to run from approximately serial number 40000 to 51000 which probably was continuous in the number produced. Lastly, third sub-variation examples were manufactured during or after 1926. Trigger guard has a different shape; slide has a greater area of vertical milled finger grooves; added Additional safety (Zusatzsicherung) now acts as the hold open device as well. These are found up to approximately 57000. Then a few examples of the first sub-variation are found from 57000 up to about 62500. This was, no doubt, usage of remaining parts. NOTE: Any commercial pistol could be special ordered with a factory nickel finish, special grip material (pearl, wood, etc.) as well as different types of engraving. It would be in your best interest to have these pistols examined by an expert.