Somethings I just wing it, the great thing about Brikwars is it's endless ability to allow this. My own theory is that yes, they get both attacks BUT only against the one target, UNLESS the mini-fig is a Hero or better. I also allow pistols to be used in melee at their firing damage just like you see in John Woo films where they stick the gun in the bad guys gut or face and start firing.
The rules state that a minifig is allowed two melee attacks or one ranged attack per turn unless you get multidexterity. so two knifes don't require any extra work to use at the same time, but two pistols would.