I have the impression that police guns of that era didn't necessarily display a chamber date? What I deem to be its typical property stamp seems to wind up in a variety of places in relation to the breech above the blank chamber onto which it's been hand stamped. Admittedly, this one's on there nice and straight, all right, but it's located too far from the breech compared to what I think we'd expect from a chamber date. Here's a link to one on another thread, which obviously gives an extreme example of being located otherwise than a "normal" chamber date.
http://forum.lugerforum.com/attachme...1&d=1575414347
I agree about the possibility of a barrel change. I didn't even notice the gouges and was going by the distinctly different color tones, frame v. bbl. Also, the finish of the top, leading corner of the barrel flange is worn less than that of the frame's similar corner? If replaced, it was fairly officially executed, with the new one re-marked, as would have probably been done by an armorer. How about a closeup of the witness marks on the barrel and frame? The vise-gouges hypothesis is suspect to me because there are no corresponding gouges on the other side.
The Parabellum is a robust, durable pistol by design. Nonetheless, things happen that bring to fruition the risks involved when shooting any collectible gun. Break a numbered part on a numbers matching gun, and its value takes a serious hit, as well as its history, perhaps more so. Your gun, though, so your choice.
Aftermarket grips, the MecGar mag are good steps to minimize your risks of this nature. The firing pin and extractor are other numbered parts commonly swapped out for shooting. The relieved/fluted firing pin style adopted around WWII (or maybe earlier?) is reputed to be safer.