Available from Morphys here:
https://auctions.morphyauctions.com/_C__RARE_LATE_WAR_COMMERCIAL_GUSTLOFF_WERKE_BCD_4_-LOT662278.aspx
Late in 1944, a number of small companies assembled a batch of K98k rifles and commercially proofed them. These are a known group of guns to the collecting community, although many of the details of their purpose remain unclear. They were assembled from a mixture of reclaimed reject parts, overruns, and other scrounged-up pieces. This example was made by F.R. Langenham in Zella-Mehlis and uses a Gustloff bcd4 receiver and Gustloff barrel, with mostly unmarked other parts. It has a commercial serial number and commercial Eagle/N and diamond/U proofs, and no military proofs or waffenamts (except on the rear sight and bayonet lug).
The various theories about the purpose of these rifles, including SS procurement (which I find very unlikely) and Volkssturm use (which I find unpersuasive as well). I think the most likely explanation is use by private security guards at factories and other institutions. With the uncertainly and chaos late in the war I think armed security was a popular idea, but private security could not have sources arms form the military. Contracting with smaller shops for a relatively small number of rifles rings true to me, but there is no actually documentary evidence of this that I am aware of.
Private security makes the most sense, and you had to have a lot of it if you were making your BMWs with labor that was…sub-voluntary. Just imagine being some poor Volkssturm dude who’d had a 98az the last time he was in a trench in 1918, and now he’s stuck with some random Vetterli while the Ukrainian security guard had a nice 98k to drop when he ran off.