Yes. This isn't the first time he's claimed that Teslas are waterproof to some extent and the fact that this seems to be a design choice he's made now and he even gives a specific use case of traveling from Starbase to South Padre Island, I do believe him. I can't wait to see these things skiing along the channel. I'll admit the idea of a chunk of steel floating across a body of water seems a little crazy, but no less crazy than sending people to Mars. I believe he'll do that also. I do enjoy the doubters though. Hopefully they can talk some folks out of their preorders so I can get mine sooner.
It will need propulsion and steering in water though... maybe they can use the giant wiper blade as a rudder.
Come to think of it, they could also make the wiper blade spin really fast and make it a flying car. Musk is a genius.
I think we can see where this is going. There is no way CT can be road-legal in some (or most) countries so they make it a boat. Boats tend to be large, heavy, slow... perfect pivot.