I've seen coins made into bowls before, both genuine coins and imitation coins made specifically for inserting. It seems to be a Latin American thing; I haven't seen it too often from Europe or Asia.
I don't know what kind of damage might have been done to the coin during the process of attaching the bowl, but it's unlikely to be removable without some damage. I suspect it wouldn't be worthwhile trying.
In any case, the shield visible through the "cross side" of the coin is clearly Spanish-American, and from what I can tell, of Spanish king Charles IV (issued between 1790 and 1808). Unfortunately, the date appears to be obscured, from those pics anyway (which are quite good) but I'm pretty sure I can see the Mexico City mintmark.
The date should be somewhere near or under the BRASD on the shield side; the mintmark, an "M" with a small "O" above it, is just above the "S" of SIGN. The mintmaster's initials, two letters like "F.M.", would be underneath the word "SIGN".
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis