Gewehr 98 (Spandau 1916) with WWII-era Stampings - Identification Help

Hello everyone!

I just came across an interesting Gewehr 98 (Spandau 1916, serial number in the k range, all matching numbers), which at first seemed to be a fairly typical rifle from the era, but with a blued receiver and bolt. Upon closer inspection I noticed that the bolt has been re-stamped to match the rest of the rifle (very similar to this Spandau 1916 example). The stock has imperial markings and a matching serial number, but it has no armorer markings, and the stock data disk has been replaced by the reinforced hole for bolt disassembly.

The most interesting part ist that the rifle also has some WWII-era stampings (one between the chamber and the rear sight, and one on the underside of the stock - barely visible but it's there). Has anyone seen such stampings before on pre-WWII equipment?

My main question is: is the rework of the bolt and the bluing of the receiver something that would have been done pre-1945 (or even pre-1918)? Or is it more likely that someone has messed with the gun after 1945 (since I couldn't find any armorer's stampings...)?

Any help / experience is appreciated!

Yes, calling it a hunch but I believe that's not a genuine stamp.

Reworks can be complex and often have more than one ordnance visit... for any prospect on good answers requires a good examination (the more complex the more pictures required); generally the main issue is the barreled receiver in detail, then the rearsight and if those sift out the biggie is the stock (looking for who did the work though this often a guess of which came first and last, though few rifles have a very high survival rate to go beyond 1940 or so... it is rare to find a G98 rifle with an trackable ord. past beyond 1942)

***do more and better pictures, astart would be barreled receiver markings followed by stock and bolt markings, - an original rifle would require many pictures to authenticate, but few get far as most rarely need to go past 15 pictures to find a problem