Yeah, looking at it on closer inspection, my cup is in two parts as well. Though it looks like it was 'welded' (for lack of a better explanation) on then grinded clean - you can see the grinder marks as they were done evenly. But it does have a faint 'tan' colour for the seam.
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"One should not increase, beyond what is necessary, the number of entities required to explain anything"
William of Ockham (1285-1349)