My opinion, your luger is authentic as far as the frame polishing is concerned.
Pictures of the inside of the grips are required, as is the complete toggle train and the receiver acceptance proofs to ascertain further originalty of your mauser
Also you may wish to run a small pick into the chamber end of your barrel, you should detect a slight ridge 4 to 5 mm from where the casing ends.
This coupled with barrel serial number, witness mark on barrel/receiver ( your 6th photo second post ) is undisputable proof of original barrel on your early Mauser.
This step was to reduce blowback from explosion gasses damaging the firing pin holder. (later abanded by mauser)
Also the rear axle pin should be stamped with the last two digits of your serial number unless replaced with oversize or replacement pin.
The backside of your sideplate should also be stamped with the first and last digits of your luger serial number.
You will also have to post pictures of the small parts to se if they are still strawed or bear the remnants of strawing.
Sear bar, left side of breechblock, firing pin, extractor, middle and rear toggle link,outside of sideplate,safety sear,safetylever,takedownlever, trigger,top of holdopen should all posses the last two digits of the serial number to be correct.
Check all these and then rest assured that you have a good one.