Kriegsmarine U boat horn?

[LE LOUP DES MERS]

I posted this in the Third Reich section but didn't get a any responses. So maybe I'll have better luck here. Wanted to get some options on this, I am not knowledgeable on anything German. I have been told by some German collectors that they believe this horn was used on a U boat during WW2. I couldn't find any markings on this horn. It also appears that the original paint was some type of OD green style color. It kinda looks like that European style/version of OD green. Is this claim true and this is a Kriegsmarine horn? or is that claim fantasy and this is not even military at all?