[@RoflsMazoy]

No, weapons like guns are "locked" for their owners while they're using it. Only if they willingly trade it to you will it be unlocked for you, and even then if your class isn't normally proficient with the weapon or you don't have some feat or ability to allow you to use it, you'd find the weapon to be unwieldy and occasionally nonfunctional. For example, most mages and healer classes can use staffs and shoot magic bolts from them, but put them in the hands of a warrior and they're just a long stick. Even passive enchantments of weapons will not function for you if you aren't proficient with the weapon in question or the wrong class for it. Most staffs can be wielded by warriors, but if it's a mage's staff they won't benefit from it's enchantments since they aren't mages.