Questions on an Odd Luger?

[dz]

Originally posted by zim
I have a Luger that has the following:
1. Dated 1916
2. Reblued and probably renumbered
3. Early WW1 proofs on the rt. side
4. 6 inch Navy barrel
5 the forward toggle is marked with a U and two dots (like a test gun might have) At one time something was buffed off under the U.

This may just be a nothing gun, but I always wonder. Any help would be appreciated. David (I will try to post pics)