Not much to see from the pictures on that GB auction, pretty poor and none of the other markings are shown. What I can see of that particular DH mark is that it is kind of pitiful and lacking detail- but so are the pictures.
I think you "nailed" the Death's Head with your 95% fake estimate. We just don't know, but do "argue or at least discuss" a lot.
I bought one at SOS two or three years ago, just to have one- knowing it was likely fake- so I "only" paid a little more than shooter price. I kind of wanted it to go with my other two "fakes" a
Simson with "1925" date added, and my "Spandau" luger; I'm still looking for a Danzig luger.
I have looked at a few DH lugers in person, and still would or could not say if they were fake or not.
Like Simpson's write up, many of the DH lugers I have seen were Erfurt pistols, and were 1917 or 1918 dated. Past that, there are those with only original inspection/proof markings and those with additional commercial proofs that date to Suhl in the 1920 era.
I find it interesting think about the "if and when" of a DH if it were ever a legit pistol or not.
I have collected some DH pictures, and I wrote a thread on mine- but it may be on the other luger forum.
Here are some of the DH pictures.
The last picture is of my DH, which is a 1915 Dated DWM luger; which also has the commercial 1920s era additional proofing from Suhl.