How many times have we thought to ourselves, or heard in conversation, "If that gun could only talk....."? Well here we have one that can fill in some information about its origin and first journey.
I am in the camp that the paper adds something to the value. How much? The key there is mating it with someone that places a value on that specific information. Personally, I'd add maybe 10% to what I was thinking my upper limit was if I was buying it..... just to have the original receipt. Someone else may add more if it fit into their collecting corridor. And others may add nothing.
It is a real niche piece. There are many more of us that would pay a premium for a piece documented as sold to the military, and a group that would pay a premium for one documented to a law enforcement organization or prison. I am thankful that we all do not covet the exact same things, as that allows me to have a few.