That would be a good idea, but I don't think it has such a thing, since it had all that water in it still. A drain hole would have let it all out. It would still have caused a rust problem, even if the rain ran and and then right back out.
Apparently 2 holes. One on each side. I got my starter back this morning. The repair place did not put anything to seal those holes as far as I can tell. So I was thinking if just running a bead of silicone caulk along the top of that seam and covering/filling those holes in the process. Perhaps also throw some multi-purpose grease on all the parts that I noticed had rusted quite a bit on the outside of the starter over the last three years. I do that with my small trailer to all the electrical connections. The coating prevents oxidation but does not hamper metal on metal contact for a good electrical current. Hopefully all my futzing around to test the electrical did not cause further problems. (I'm looking at you, ignition switch)