If it is just a dent to the outside of the plastic and not all the way through, it will probably be fine, but if it were me, I would still want a new one. If it is a crack or hole all the way through, nothing should leak out, but it could. Also, since Kinetik batteries are sealed, they have no way to add water back into them if they leak. So if they vent, either through a hole or through the vent caps, they should no longer be used.
Cliffs: Get a replacement.