An acquaintance brought over a Remington model 11 with @20" barrel equipped with some kind of weaver?(I think) compensator/choke.  It had all the makings of a really ugly gun, cut down barrel, re-done rear stock, ill fitting pad, and...........

US Arsenal markings!!!! stamped on the receiver and barrel!  Right next to the flying ducks that you would traditionally find on this era of gun.  

I plugged in the date code into a website that will date firearms, and it gave me two dates, either in 1943? or 1966.  What do you make of this.  I figured it might be a Vietnam era gun, sense I don't think the "ducks" were on the WWII generation guns.  Is this some kind of "jungle/trench" gun from Vietnam?  Or what?  The flaming ball and U.S. were clearly stamped.  I couldn't believe it.

The Army Air Force bought them in WWII for training gunners.  They'd use them to practice shooting skeet before moving on to machineguns.

My dad has the exact model you describe, to includ the Ordnance marks and the comp.  He uses it duck hunting with a different barrel.  

They're great shotguns.

Ross

The Army Air Force bought them in WWII for training gunners. They'd use them to practice shooting skeet before moving on to machineguns.

As did the Navy, Marines, Army, Coast Guard, etc.

I figured it might be a Vietnam era gun, sense I don't think the "ducks" were on the WWII generation guns. Is this some kind of "jungle/trench" gun from Vietnam? Or what?

The first WWII-era shotguns retained their civilian markings while existing parts stocks were exhausted. It's not unusual to find martial Ithaca 37s with commercial duck and pheasant scenes on the receiver (as well as many other WWII shotguns). The Navy was still using Model 11 Remingtons aboard ship as late as the early sixties.