You'll never have any trouble if you play all of your herds the same. For example, if you have 5 herds and all are either 2 hand weapon (which is the only way you'd want to play them anyway) or hw/shield, then there's no confusion and a little bit of modelling liberty will actually be encouraged.
But if you have 2 herds with hw/sh and 3 with 2 hw, then people will get confused and will not be happy.
Regardless, you really only want the 2 hand weapons. It's much better than the shield option.