No, sorry, "pistol" and "duelling pistol" are 2 different kinds of weapon.
Your dwarf may ONLY use a duelling pistol if he has a skill that allows him to use ANY kind of ranged weapon/blackpowder weapon.
So no 13" shooting pistols for your midgets unless they have the skill I'm afraid... But have you considered crossbows? I mean LOTS OF THEM!
(I have 5 crossbows in my Witch Hunter Warband... at least one of them is BOUND to find an angle and shoot in every turn).