I would expect that the cars would be shipped by boat without the ESS. They would be packed in shipping containers that would be loaded/unloaded by crane just like any other container.
There would still be one question. When shipped by air, it's easy enough (although expensive), to send it directly to San Carlos. By ocean, they would arrive someplace like NYC or Baltimore. For cars that are not destined for CA, it would make more sense to install the ESS on the east coast.
Maybe it doesn't matter. Most of the cars are probably headed for CA anyway, the few that aren't probably don't warrant the extra trouble to save the shipping back and forth.