I have this 2000 penny that i found in my pocket change that id like to try and get some input on. I dont know if its an error or been altered some way some how. On the obverse and reverse of the penny it appears to be missing the copper plating, yet its present on the rim of the coin. Obverse and reverse both show heavy linear plating blister marks. Some have said the copper has been removed, some has said its been plated ove with zinc, the problem i see with either one of those theories is the coin weighs 2.5 grams, like a normal 82 - present penny. Would anyone have any insight into this?