Error Coin Or Ground?

So a while ago, I found this dime in my cash drawer. It's almost completely smooth on one side, and the obverse is looks slightly worn.

My question to you all is, does this seem like a man-made condition that this coin has?

My thoughts is that it was ground down by a person, mainly because on the obverse, there is almost a dark ring like coloring on the coin where it is worn, which suggests to me that it was ground. But the back doesn't show many signs of this, and there are no rough edges on the coin anywhere.







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