The serial number establishes the date of manufacture as well as who made it. Does the front toggle link on top say "W+F" with "BERN" under it? The Swiss didn't mark their Lugers as generously as the Germans. Below is my P'06 Swiss military Luger made by DWM as a kit and sent to Switzerland to be completed there in 1910. It's in the 12000 serial number range. Note the proof marks in the same place as yours and how few they are. DWM provided the Swiss with Lugers until WW! forced them to stop deliveries and the Swiss found it necessary to make their own.
