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The creator of this 'coin' worked at the Hamilton Mint
Too much supposition this statement.
H. Alvin Sharpe was a noted artist in New Orleans and is credited with creating the Mardi Gras Coin.
While it's true that he worked for the Hamilton Mint for a time, it would have been strictly as an artist, not in the physical coin making part of the minting process.
In fact, unless I'm mistaken, there isn't anything to show the origin of the dies used, so assuming it's from Hamilton or that Sharpe had anything to do with the coin would be improper, at this time anyway.
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but as mentioned, no numismatic value.
This is almost certainly incorrect also. I don't know a lot about dubloon collecting, but a quick internet search shows it's an active area of exonumia.
http://www.ccdtclub.com/https://www.mardigrasdoubloons.com/homeIf the OP could ID the original dubloon who's dies were used that would go along way to establishing value, but I'd bet a healthy amount there's a Mardi Gras collector out there that would love to own something like this.
Not saying OP can retire on it should he decide to sell, just pointing out that altered coins are collected by all sorts of hobbyists so we shouldn't jump to conclusions.