No.. It is not a Missing Clad Layer Mint Error. As stated it's Environmental Damage. Exposure to dirt, soil, sand, chemicals and the elements like water can change the color of clad layers on clad coins. I metal detect. Here are examples that I have found -
Another thing is that a Missing Clad Layer usually involves one side of a Clad Coin. Any side either Obverse or Reverse. Here are example from my collection -
Like the others said, it is just environmental damage. The fact that your coin is missing the reeded edge is probably due to (intentional) spooning or perhaps it was caught in a clothes dryer for some time. Chris
Start your own unique separate thread. Missing clad usually is on 1 side of a cladded coin. Not both sides. There are many ways clad coins which are Cupro-Nickel can tone a dark color due to Environmental Exposure. I have shown plenty of examples. Posting a picture is simple. Choose the upload file, select the picture from your computer or cellphone. Then upload. Ask a friend or young person in your family to help.