Good show! I passed on erroneous info on the Rheinmetall pistol; it is clearly not just a copy of the Browning as three books said. I guess they are so uncommon that the "experts" had never seen one and just made some assumptions based on pictures. (I hate that; it a writer doesn't know what he is talking about, he should at least say so.)
Of course the Dreyse was made by Rheinmetall. Most are marked "Rheinische Metallwaren und Maschinenfabrik" which the company later shortened to "Rheinmetall" (good move!).
BTW, does that gun fire and eject? I think the firing pin originally had a long nose like the Dreyse so the firing pin would also act as the ejector, like the Browning.