Its a RC to begin with, the only thing relevant to the discussion is the barreled receiver, the rest uis just parts thrown together by the Russians...so the stock, bolt, bands, TG, FP, etc have nothing to do with the context of the gun.
Many early SS conversions were scrubbed, and commercial nitro proofs applied since they could not get their weapons through normal Wehrmacht channels...many guns were obtained by "midnight requisition" or commercial channels, then reworked for use, hence scrubbed receivers (hard to prove they were stolen army guns if there are no roll marks)...the commercial proofs look correct, I won't hazard a guess on the totenkopfs…
Gunboards have fallen from their lofty perch as the best Gew 98/98k board out there, many of the true experts there have either passed (John Wall for example), and the quality there has fallen way off because of this. The best board by far, as the OP knows, since he posts there, is www.k98kforum.com