The wearer could eventually be Leutnant Günther Prinz von Schönburg-Waldenburg, 2. Eskadron of the GDC in the Rangliste 1907 (page 327).
One find him in the 1911 Rangliste, page 40, as Offizier à la suite der Armee, the same in the 1913 Rangliste (page 42).
In the Ehrenrangliste 1914-18, one...