No, bunnies should never be bathed except for health reasons, some buns do need bum baths but I would never fully bath a bun except under direct instruction from a vet.
Rabbit fur is designed to keep water out, even a bun that's been sat in the rain for hours will most likely still have bone dry skin, if you soak a bun to the skin they will still be damp for hours and hours no matter how hard you try to dry them they will be cold