Are the pistols restricted to one hand because the game treats them as "whips"? Thats what I've heard...
Nope. In baseitems, the EquipableSlots field is what determines what goes where. Something that can be equipped in main hand and offhand looks like 0x1C030. Main hand only would be 0x1C010, offhand only would be 0x1C020. Whips get a 10 on the end, shields get a 20 on the end, and something like a shortword gets a 30, which is 10+20. With me so far? If you set a whip to 0x1C030, it would be dual-wieldable on the spot. Boom, done. I've tested this, it works. I think the concern of dual wieldable whips is that there are some REALLY good whips in game already and dual wielding them would be crazy since they are eligible for weapon finesse. But I digress. The point of this is that the pistols ARE set to 0x1C030, its just the weirdness as 'ranged weapons' as Bluebomber already stated.
Now, the pistols aren't truly ranged weapons - they are just sticks you hold with a script use on them. They could possibly be defined as not ranged weapons, since, after all, their functionality is entirely limited to a script that runs from an on-use ability. Maybe they need to be ranged weapons to calculate their AB? I don't know.
Would it be possible in the future to list pistols under 'simple weapons'? They're supposed to be one of the most simplistic missile weapons - very much in the same manner as the crossbow in that all it takes if someone to show you to load, point, click.
Pistols rarely backfire and never destroy themselves in a horrible explosion, so I'd say Exotic represents you having the knowledge of proper maintenance, cleaning and inner workings of the pistol. If you made them not exotic, they ought to have a higher chance of failure and a chance to be destroyed and need repairs from the gunsmith unless you have Exotic.