Okay, now that we have a different Luger to look at. Here are my observations on THIS pistol.
As Ron has mentioned, the upper receiver appears to be a legitimate Navy Receiver from 1916. The barrel appears to be a Krieghoff manufactured replacement, and yet it is numbered to the upper receiver.
I don't have any references available to me at the moment, but I don't think military (Navy) receivers had 5 digit serial numbers... somebody correct me if I am guessing wrong on this fact. I have been known to be wrong in the past on at least some things, just ask my wife!
The right hand ZERO on the back of the rear toggle appears to have been added or overstamped on the original number (possibly an "8" or a "3" and is irregular in shape. If it were the original number stamping on this toggle, it would have been made with the same stamp that was used on the left hand ZERO, but is definitley a different size from that one. (Forced Matching and poorly done...Thanks Doug).
From what can be seen in the provided photographs, there is no serial number present on the lower frame above the trigger guard. This is a red flag for me. It is difficult to tell if it is parrallax distortion in the side photo, but it
APPEARS that the front of the frame has been ground down or shaved so that no number appears there.
Since the barrel was replaced, I believe that the front of the upper receiver was shaved to match the new dimension of the lower so that it does not protrude from the lower frame when assembled, which would be a giveaway that the gun has been boosted.
It is possible that the number on the left side of the upper receiver may have been enhanced by the addition of the leading number "1" and the trailing "0" so that the original number may have been 540 instead of 15400.
No one has yet mentioned that this gun has been modified with a police safety installed over the sideplate...
While it is certainly possible that all the above modifications were made when a WW1 Navy gun was rebuilt into a gun for issue and service with a German police agency, I don't have much confidence in that theory. I think the gun is the product of Waffenfabrik USA to be sold as something that it is not.
Just my $0.02
