U-Boat Flare Gun

[c1a1]

I came across a Kreigsmarine flare gun with 2 barrels. Its like a sxs shotgun in configuration. Have seen many single barrel German flareguns, but never a double barrel type. Action is opened by pushing on the trigger guard as in the standard Heere types. The entire gun looks to be nickle plated? Owner has documentation on U-boat it was "liberated" from. Does anyone have any information on this item? Thanks in advance for any info received.

 

[Scarecrow]

Looks like this:

Marstar sells them for a little over 600$

 

[c1a1]

Flare gun

The trigger guard was more curved. Finish was very bright. What are the markings on the Marstar models?