I would think it would be almost impossible to detect in a period photo if a soldier were wearing a screwback EK1.
However, in this period photo the Hauptmann does appear to be wearing a WWI screwback EK1 which has rotated 45 degrees on his left breast pocket.
However, in this period photo the Hauptmann does appear to be wearing a WWI screwback EK1 which has rotated 45 degrees on his left breast pocket.