If it was made of steel it would then be a ferromagnetic planchet which means it would be attracted to a magnet. Try it If it doesn't stick to the magnet then you only have 1 option left.
Copper plated zinc planchet. The copper was stripped off. It is not a steel planchet. Zinc is not ferromagnetic. Zinc has a silvery color which new collectors mistake for steel when the copper plating is missing.
Yes, in this case the copper has been stripped. All of these show a dark discoloration to the zinc. They have a very lifeless and dull appearance.
Some unplated pieces do make it out of the mint. I’m not sure how you would go about proving this is one considering the condition it’s in. Usually when the copper is peeled off the remaining zinc core would be dull. The detail would also be lacking. When an unplated planchet is struck with dies it comes out shiny. I’m sure if it were put in circulation for a few years the shine would wear off.
It's very easy to strip the copper off, too. Soak it in ferric chloride, the same stuff in Nic-A-Date that reveals the date on worn Buffalo nickels. It strips the copper and leaves the nickel, or in this case, the zinc. It's the same chemical used to etch the copper when making electronic circuit boards.
