Copper was removed after it left the mint. I have several of these. What I've learned is the imperfections on the surface are reaction between the copper and zinc when coated. Telling us that your coin had the coating at one time and was removed. A true uncoated Zincoln will have a smooth surface. I'm sure someone will correct me if I'm wrong here so let's see what they have to say. Here is some reading material for this. http://www.error-ref.com/unplated-cents/
