They're just grips.... I just roll them up and put them on.
Since the grip is supposed to prevent the bat from slipping in one specific direction (down the hands) only and not the other way (i.e. "slipping" up the hands which generally doesn't happen anyway), there could be one "better" direction than the other..not necessarily for all grip types, but potentially for some.. For e.g., I always observed that for snake/fish scale grips, the 'C' always faces downwards out of the factory/store, meaning that is the supposed direction? But yea, not many would care