God bless you and thank you for your service, Marine. That duck recipe actually sounds pretty good. I'm getting a bit tired of just heaving my Canada's (and lesser diving ducks) into a gumbo just to use them.
The barrel guard is a fairly common item in England, for use on traditional splinter-forend equipped shotguns. It offers two distinct advantages that I know of, the first is to keep your hand from being burned by the hot tubes of a gun that is being shot alot (more of a driven-game issue than what we tend to see here). The second advantage (and perhaps the greatest) is that it acts to force the correct placement of your leading hand on the barrels, well in front of the splinter. Another mild benefit that I have discovered is that it helps keep my sweaty mitts off of the barrel steel (which is a good idea on any gun, even more-so on old, brown, Damascus tubes). As best as I can tell, (Blanch was bombed-out in the blitz on London in '42, so the records aren't available) this gun was made around 1886-7, well before the advent of the Beavertail.