Would appreciate some help with a WWII Remington Model 11

I'm helping a friend sell a WWII "Military Finish" marked Remington Model 11, and would greatly appreciate some help in establishing what he has, and a rough "ball park" idea as to value.
The gentleman's father was a Navy lieutenant (Gunnery Division Officer) on a carrier in WWII who was presented with the gun at war's end. I'm guessing there is no real collector value to the gun as the barrel and receiver serial numbers do not match, and the barrel is blued while the receiver appears to be a dull blue/parkerized finish. In addition, the fore grip and stock appear to have a different finish. There is a spot on the L/H side of the stock that may indicate an ordnance stamp was sanded off.
As best I can determine, it has approximately an 18" barrel with a Cutts compensator on the end with no choke markings on the barrel. It has the Ordnance ball on the barrel and receiver, with the "Military Finish" marking on the receiver.
I've posted a few pics of the gun, and would be happy to provide more if it helps. While I know a little bit about M1 carbines, Garands and 1911's, I have no experience with the military shotguns. I would very much appreciate any info, estimates of market value, and suggested venues for selling for this gent. Email me with any questions/request for additional pics at: kiko1(REMOVE)@ bendcable.com
Thanks in advance to you all.
John

Barrel is 20", not 18"

If it was mint and matching , I'd say $1000 or maybe a bit more. As it is not matching and the fore end is from the wrong time period , I'd say no more than shooter value , maybe $2-300 or so.
Chris

You say his father was "presented" this gun at the war's end? That whole bit sounds a little off to me. The gun looks like it was cobbled together from parts ranging from old to new (well, newER anyway). And for as little use as these realistically saw during WWII it's highly doubtful that an Armorer would have had to change out so many parts to make a training gun functional. Sure, he may have swapped the barrel out himself after the war so he could hunt with it. But that also hurts the value.
I wasn't there so of course I'm not saying the story is definitely false, I'm just saying that if he goes to sell it, he may want to steer clear of that story and sell the gun for what it is.
In the world of milsurps we all know to pay for the gun, not the story. Unless of course it can be verified. Many times the story doesn't jive with what the gun tells us. In this case, if I came across this gun at a show I would have thought everything I just told you, assumed I was being told some made up story to make the gun seem more marketable and passed on it because guys tend to charge more for the story that goes with the gun.
I'm not trying to beat you up and please don't take it that way. The world of military shotguns is absolutely inundated with forgeries and guns cobbled together to make them something they are not. Military shotgun guys tend to scrutinize more than the average surplus collector. The only way to make sure you're not being taken for a ride is to stick to pure, 100% accurate guns. Otherwise they are simply shooters.

said shotgun is likely one of those converted to 3 shot magazines.. Air Force Skeet teams used them...i owned one for awhile, it did have a unit marking...not all were marked as such.
the cutts was added at the same time..
mine was an early gun, and had nice wood, and finish...sold to a collector for 750.00 last year...yours doesnt look to be as nice...id say a real price wouyld be 350.00 to 450.00

Chuck , some of these had the cutts right from the factory , including the short bbl riots . The tipoff is if there are choke markings on the barrel . If marked , then the cutts was added . If never marked , it came that way , because the choke was whatever adapter you put in it , therefore the choke marking would have no meaning.
Also , some three shot " sportsman " model were also made and delivered in WW2 including riots . Don't ask me why .
Chris