Swiss cheese Luger

[Mauser9x57]

I named this Swiss cheese because I thought some of you knowledgeable people might shoot holes in what I was told when I bought this pistol.
The story was that this is a 1920 rework that was sent to Switzerland, The 7.65mm barrel was then installed by the Swiss and has no proof marks.
The numbers match but some parts have no number. The magazine is unnumbered with a wooden bottom. I had a 1920 rework before with the typical 3.75" barrel, and the chamber date and stock lug ground off. I know if this is a 1920 it is not typical.
So is this as I was told or something put together by Billy Bob and associates? I bought it for a shooter price. I am sure I don't need to say I am new here and am no photographer. Thank you.
I am somewhat of a weirdo because I am only interested in 7.65's with 4.75" or longer barrels. They are beautiful to me.
Dave