The dentils will wear flat like that as it approaches the AG grade.
Here is a slabbed G-6 on CoinFacts:
As @DoughDeo posted, the raised edge could be caused by someone tapping on the edge as they roll it.
What is the diameter? If greater than normal, somebody may have pounded it between two pieces of leather to enlarge the coin and hopefully pass it as a dime of the same design.
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While the upturned rim fin does indicate "spooning" that would not make the USUAL wide rim flat. The denticles are still visible where they should be next to the field. So I'll agree, very worn coin that was probably "spooned."
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It looks like someone started making a ring from a well worn and damaged half dime.
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The dentils will wear flat like that as it approaches the AG grade.

Here is a slabbed G-6 on CoinFacts:
As @DoughDeo posted, the raised edge could be caused by someone tapping on the edge as they roll it.
That was my first thought too but it would be so small. From the raised rim I think it was probably going to be some sort of jewelry.
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yes, spooned
BHNC #203
An unfinished attempt at coin jewelry..... Cheers, RickO
Yes, it was hit with a spoon or something to flatten the edge, but the dentils are gone from wear...nothing more.
it is not a counterfeit, it is damaged
on the obverse, there are indents made with a small punch or nails which caused the reverse to wear more at those dented spots
The coin had severe rimgum disease and the dentils had to be pulled at the sub-treasury. This half dime has not yet been fitted with new teeth.
What is the diameter? If greater than normal, somebody may have pounded it between two pieces of leather to enlarge the coin and hopefully pass it as a dime of the same design.
While the upturned rim fin does indicate "spooning" that would not make the USUAL wide rim flat. The denticles are still visible where they should be next to the field. So I'll agree, very worn coin that was probably "spooned."