Your rifle will answer that. Some rifles shoot better with a wad and some with out. Also the brand of powder you shoot makes a difference. I find that when I shoot T-7 with PRB, a wad increases accuracy because it protects the patch. T-7 can tend to eat patches in rifles. The wad gives it and you that little extra add.
Before you try the wad, remember the load of powder might need to be adjusted too. With a wad I tend to shoot 5 grains more powder then with out. But all rifles are different.
If you have no wads, just take some old T shirt. Tear off a strip and push that down on top of the powder, then set your patch and ball. Old timers used to also use Corn Meal. 20 grains of Corn Meal poured on top of the powder, then the patch and ball also protect the patch. Mountain Men they claim also used paper wasp hive. I actually tried that once. It was fun to try, but made no difference.
So all you can do is try. And let us know your results.