It arrived about 20 minutes ago. It's marked WMF, although I can't find the exact mark elsewhere through Googling, so I can't date it.
I would guess that the bowl is original, as it fits snuggly, the base has been ground to fit nicely into the metal cup and there's corresponding surface-wear on the inside of the bowl from the securing screw. But, of course, that's just my guess and they could be later additions to the bowl.
And it's silver-plate on brass... which someone has cleaned a little too vigorously, so I'll have to have it replated at some point.