It looks like a milsurp Mars Skybolt. I haven't seen a base, I mean at the very bottom, like that before, it may have been caulked on a roof or mount. Is it 6, 12, or 24 volts?
24 volts, 28 volts, it all feels pretty much the same when you are poking around places in a 1960s vintage UH-1 that you shouldn't be poking around in. There are also some marine electric systems that get pretty goofy, and from the looks of that base I can picture it glued to the top of a SWIFT Boat checking out sampans in the Mekong Delta.
Yep, I heard that somewhere else. I think it is ex-US Military but not sure what it was fitted to. And that's a s**t load of glue/resin they used to stick it on!