A conehammer with finned barrel is listed on
http://www.collectorfirearms.org
"Handguns M-Z" section.
This is the 2nd time I saw a finned barrel Mauser. The other one was pictured by Chinese police. That one was a Schnellfeuer-like pistol in poor shape (like others C96s pictured).
So finned barrel is not totally out of scope.
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But this one was refurbished, and looks like having a welded on barrel. That Schnell I mentioned earlier, no idea. The picture was not clear enough. Remain a myth.