I am sorry to be the first to tell you that this may very well be an original navy cap, yet it is a post war navy cap with (fake? - I am no specialist for these) TR insignia.
Why only why do fakers think silly stamps do any good?
Navy with an RZM-stamp! You're kidding?
"Wir sollen auch unser Leben für die Brüder lassen" (1.Joh.3.16):
zum Gedächtnis Wilhelm Schenk. Er starb fürs Vaterland am 13. Juni 1916
The RZM stamp is not something associated with this Mütze as indicated. A better photo of the interior including manufacturer is needed. NH
RZM stamps go on Political items not Navy ones, looks like a post-war cap pimped up to look WWII.
Let all be thankful for the fakers Love of fake RZM stamps, and their stupidity.
I agree with the others--it is a postwar BRD Marine visor with repro insignia.
NEC SOLI CEDIT