Need some help with first Luger

[5bassman]

Here is a little clearer picture of the stamp on the front grip strap. Looks to have been done after issue. Starts off with 2.M.G. R??8 . The gun isn't mine until we decide on a price that is fair for both of us. Thanks for all the help.
BTW, in the third picture you can see the M under the serial on the frame below the barrel serial.