It's period done (I’d drop the sling ring as its not period and looks tacky), and as Mike states probably reworked at some lower level repair shop. Repairs were done in an unbelievable array of low-level shops and facilities.
I have pics of two man operations in shacks, one in what looks like a freaking tikki hut! Some in little shops too, where you see a few banged up rifles or actions being taken into a small shop by a bunch old timers.
Unlike in WWII, period pics of WWI repairing rifles is very common and they really are a varied lot as to skill level. Of course rifles needing substantial work, battlefield salvage would probably be sent back to an ordnance depot or maybe even an artillery depot or arsenal for repair and salvage (Storz goes into this in some detail, especially as it relates to Bavaria - Ingolstadt & Amberg)
I like the rifle, especially now that I get to see it.. Ambrose reported most of his rifles, but he rarely sent good pics of them, never broke any down for BC's etc.. this rifle has the original JP Sauer (S&S) made barrel, and they did a lot of them- they seem to have been mostly a barrel maker.
VCS is a tough maker to find, about equal in rarity as Sauer, - CGH being the most observed of the consortium. I am of the opinion that the consortium shared serial numbers, possibly assigned blocks, but not independent serial numbering. As if they independently serialed their production would greatly exceed Storz figures, several times over, and they are far too scarce today to have been made in such numbers.
All the Suhl firms are hard to find, and it is hard to say which is rarest as there is no way to document production besides observations- Simson is higher than most in observations, but that might be just because I seek them out aggressively? By serial range Simson is by far the rarest, but as I think the consortium shared serialing ranges, so no way to tell for sure.
They are all damn tough to find really nice and matching though.. original factory matching in really nice condition would command a high price, - 98k ranges.