The more I look at these photos the less I like this rifle. I'm now nearly certain that the skulls are fake (the white out in the markings is a good way to hide stuff), which makes sense due to the anomaly of the missing commercial proofing. The wrist marking as well, just isn't quite giving me any good feelings. Lastly, that band arrangement is not what the SS did. Whoever told you to pass on this one was wise, most likely the faker didn't understand the meaning of the skulls in relation to that reworking being done to them.
You need to learn to separate the different types of SS reworks and what they are. For one, there are early Gew.98 reworks where rifles were converted to a short version of the Gew.98 (not quite 98k's). These early Gew. reworks are the ones with all of the different skull markings that have the lazy S, SS, gull (or whatever), etc. and have commercial proofing. These were all done in one place most likely. The SS2 skull marked guns were a completely different animal, and not Gew. reworks specifically, but rather mostly reworks of the Gew.reworks, along with other reworking of existing 98k's in SS inventory. The SS2 facility (of which I am 90% certain I know where/when these were done) was not the same place as the original reworks. I sounds complicated, but it's actually simple.
One thing that I discovered since the last book, or at least realized since, is there is an oddity about the commercial proof marks on these early Gew. reworks. If you notice, none of the commercial proof markings have the proof house marking on them - upside down heart with fir tree is Zella-Mehlis, Sole with Axe is Suhl, Antler is Württemburg in Oberndorf. These proof house marking identifiers are universal on other commercially proofed rifles. So, the SS Gew. conversions were pressure tested at what I am starting to believe was a branch office of one of the proof houses, somewhere in Berlin is my feeling, or outside Berlin. The German proof law of 1939 allows for branch offices of the official proof houses, so it would be legal. This may be the meaning of the additional numbers with the commercial proof marks.
I have been studying the SS depot system and rifles a lot for this next book and have some cool revelations coming, most of which I am biting my tongue right now trying not to share so I don't ruin some of the surprises.
