I'd like better pictures. maybe it was lightened in weight by nitric acid bath, which would affect all surfaces at the same time,or just one side if one side was only treated with it, it's also how you strip off the copper plating on zincolns. it's roughly 16% lighter than it should be, if the surfaces show corrosion in a clear picture I would have to go with the cent being thinned post mint, and not a thin planchet pre-striking. the bubbling of the nitric acid as it dissolves the copper will leave pitting. there's all kinds of these experiments to tamper with coins on youtube. surface condition is everything to determine when it happened. if it shows any sort of corrosion, it's not going to get attributed as a thin planchet error, they will assume it's been tampered with instead. also, this is part of the method to remove copper and silver and a lot of other contaminants from gold (not platinum) and make it pure again. but that's a much longer story as well as how to reclaim silver or copper or both separately once it's dissolved in the nitric acid solution. And FYI, disclaimer: there are toxic fumes, gets hot, and it's an acid, so if I inspired anyone to play around, that's on YOU, I warned you. don't try this at home without learning as much as possible about doing it safely first!