They might not fight, but keep an eye on them because they might object to the other mating with the hens. I had a couple that when one of them was mating a hen, the other would run over and peck both the rooster and hen on the head. A couple of times one of the roosters ran over and ran into the mating rooster and hen, knocking him off.
Didn't fight each other, but the hens got the worst of it from pecks on the head to torn flesh from spurs dragging when the rooster mating her was knocked off. Ended up having to pick a rooster to leave and one to stay just for the sake of the poor hens.