The male Tuber in the Ruby, Sapphire, and Emerald version of the class uses different colors than actualTubers. This is because the Tuber Trainer class uses a different color palette than the Swimmer class.
Though the Sis and Bro class exists in FireRed and LeafGreen, there are no male Tubers in FireRed and LeafGreen.
There exists beta data for a Generation IV Sis and Bro class, though it is assigned to no Trainers. Sprites for the class exist in the Generation IV games, however, they are of a male Swimmer and female Tuber, rather than a male Tuber and female Swimmer, as was done in Generation III.