No, as even though it has multiple barrels, it is still only one gun, or marker. I guessing, to be a true Hammer set up, it must be two separate markers that are placed on a frame work that holds them both together. Now I am not totally positive about this, but I believe that it also must have some kind of firing system that allows one, then the other, to fire. It may still be technically okay to have both markers fire at the same time, but it may not be totally field legal. If another Hammer wishes to correct me on this, please do so.
Not entirely true. Granted, do their weight, it may not be possible to use for a long period of time, at least in a man portable sense. But they can be used, and are not as heavy as say a 1:1 scale reproduction 105 mm cannon.