Thanks to all for the help so far.
Appears poured, which would be good, except for two things.
Thanks to moxking's observations I'm pretty sure this is a replica. Perhaps the writing on it may give someone here a clue to what it's a replica of?
How did you acquire it?
So long ago I can't be sure but I believe I bought it at the 1964 World's Fair in New York at one of the Pavilions. It probably just caught my eye as something unusual. I don't remember paying a whole lot for it. Unfortunately, any documentation I may have had for it was lost while moving house many years ago.
I'll probably have it tested for silver content at some point for curiosity sake but I didn't want to damage anything that might have been authentic.