A) you can't really fault ANYONE for setting their price. You guys know where we live, you know how the game works. Walk the other way if you have a chip on your shoulder with regards to what is being offered and how it is being priced. His price is absolutely
right no matter what it is, because HE owns the gun. If you think the box is worth
nothing and if you are dead certain that his price is $100 too much and the box is worthless, there's only ONE way for you to fully correct the situation:
pay him exactly what he asks, throw out the box yourself and then sell that revolver for $100 less to the first buyer. Then you can sleep at night.
B) much of the buying public will perceive that gun
with it's original box as more desirable simply because it gives the item a "feel" that someone cared about it and/or it's gotten less use and/or it's had less owners.
None of that might necessarily be true, but it still adds to the desirability of the item. This is long since been established even if you don't care to agree (which is also perfectly fine, no doubt!) and if you find a comparable gun that you'd rather have for _____ reason and it has no box, you'd do well to go whichever route is most comfortable for you. But it doesn't change the general market and the general market gets a warm fuzzy when there is a box and goodies original to the gun that comes along with it.