Some parts of the sequence where Carter, Newkirk, and Kinchloe throw the hand grenades over the fence to destroy the high velocity shell factory are re-used in The Well (1969) - except the thing that is destroyed then is the water works at Hamelburg.
Per the title, the real Mata Hari was the stage name of Margaretha Geertruida Zelle (1876-1917), a Dutch exotic dancer and courtesan who was executed by firing squad for espionage during the First World War.
Major Hochstetter appears in a civilian suit and leather coat, rather than his usual Gestapo uniform.
The black and white photograph of Schultz that Major Hochstetter shows Eva Muller is normal for that era. Color photography did not become common until later. However, the photograph does not seem to be one from Schultz's personnel file, as this is not the style of personnel file pictures. Personnel files are normally where Gestapo gets its pictures from.