This is an example of the sort of plates being made by a company in Poland to order from a man living there. All the plates have REPLIKA nnnn stamped into the back. The problem is that some crooks scratch off the stamping and try to sell the plate as genuine.
This one is a Vatican plate and is actually a very, very good reproduction that fooled several knowledgeable collectors. It is of course a mint, unused plate and you must always ask to see the back of a mint plate when you are buying it. This one was REPLIKA 0303 and no-one is certain how many reproductions/fakes this man has had made.
Mint plates like this must make you think the worst of the seller if he says it is a genuine used plate. Mint, unused plates that are genuine just do not exist from most countries.