Dimes are not plated, they are clad. Clad is like an Oreo cookie, a layer of copper between two layers of nickel/copper. I'm thinking that, due to the sharpness of the strike, your coin is just discolored. If you could post a pic of just the edge, not from an angle but straight on so that all we can see is the edge, you might get a more accurate opinion of your coin.
I can see the layers in your edge pics, so no, it's not missing a clad layer, just discolored due to something in the environment it has been in. (buried in the ground?) There was a chip (hole) in the die used to strike the coin, leaving that mark on the chin. Spender. Keep looking, though. There are errors out there to be found.