No it matches pretty much to the mark on the ring except for the square border. But as far as I can find he's the only one with a plain old Z mark. Of course possibly more that I'm unaware of.. So for now that's as close as it comes until we find another with the square around the Z mark.
Hi Spitfire, Franze Ziehme is listed as a goldschmied from Artern Germany which by the way was in the former GDR. Best!