If you mean pea comb + rose comb, that a geneticist will call a walnut comb, then yes they definitely can be on both males and females.
Chanteclers are an example of a breed with walnut combs on both males and females.
If you mean a comb that looks like a walnut, and you do not care what genes are involved, it is more likely on males than females just because of size (a rooster's comb is more likely to be as big as a walnut, while a hen's comb is more likely to be smaller.) Silkies are a breed with a comb that looks like a walnut (especially in males), but I've read that they can sometimes look like that by having just the rose comb gene and some modifiers, with no pea comb gene at all.
