The edge of the coin looks 2 colors instead of one like a penny. The penny is struck very well also, wish it was a proof without an s! lol Could this be a dime since it weighs 2.37g?
That is a over abused zinc cent. The silver you see is the exposed zinc. You wouldn't see that on a dime. It also wouldn't be copper plated.
Even if it were brand new and weighed that, it is still within the .13g +/- tolerance. This coin is circulated, damaged, abused. And the weight loss is normal. Not a dime planchet. It couldn't have full cent rims or be copper plated if it were a dime planchet.
With the foreign substance on the reverse, it could add to the weight. Could be cement or plaster maybe?