It appears to be hollow, & permanently seamed together, except for the base and the little dome, which are attached with screws.
If you tap on it, it sounds about like 19 gauge steel. About the same as a fender on an 60 year old car.
There don’t appear to be any other holes or attachments for wiring or valves or any such thing. It just appears to be a big ornament, but I don’t understand that little arrangement with the slanting shelf on the base and the little bits of steel angle.
This is my current theory:
This was the ornament on top of a display of cans of motor oil from the 1960s In a New Mexico gas station.
The funny bit of bracketry was to hold a little sign where you could post the prices.