Could be. If it is, it's a very minor case and he should heal without losing any of his comb. How cold has it been at night? Do you have a thermometer in the coop so you can know how cold it gets?
Frostbite occurs when water vapor from the chickens respiration at night condenses on the tall combs and freezes, injuring and sometimes destroying tissue. When tissue is destroyed, it turns white, then later black. If his points turn black, he will lose them.