Pretty!
But I wonder, will the rust eventually eat through those steel pipes?
It could be a capacitor, but in that era, I would rather guess it is some sort of inductive coupling, similar to the Kliks-on we see on slightly more modern units. There is something very similar on the '47 Shelvador and it, too survived being under water.
Sealed, so I didn't open it, but none of my tests showed a response which would have suggested a capacitor.