There seems to be a spot on the rim below Lincoln where the plating seems to be missing or peeled away. You very commonly see patches of missing plating when a coin has been electroplated; this is where the wire was attached to the coin.
But, perhaps a quick test will convince you: see if it sticks to a magnet. If it doesn't stick at all, it's been zinc-plated. If it sticks only weakly, it's been nickel-plated. If it sticks strongly, it's solid steel.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis