A few years back I saw a similar pistol on Simpson's site. It had a DWM military barrel extension with the date over the chamber, but a Swiss .30 caliber 4.75" barrel. It was a quality rework, very nice and offered for around $1,400. I remember the pistol well because I strong considered purchasing it. I forget who I spoke to at Simpson but they said they see a few like that from time to time, which they defined as Swiss re-works of Imperial militaries that were then sold into the Swiss commercial market post WWI. I found their explanation and the pistol both fascinating and sort of regret not getting it. Given Ron's comments at post #36, absent other information to the contrary I have to wonder if this may be another example of the type.
Determining frame vintage requires real expertise. If you compare Ron's post #36 in this thread to this tutorial on frames
http://luger.gunboards.com/showthrea...Frame-Tutorial that will enlighten on some of the characteristics to consider.