A copy of what, specifically?
Who are these dorks who go around spreading fake doubloons on beaches? Makes me glad I'm in Kansas!
From what I've heard, if you visit the mel Fisher Atocha museum, tourists can actually buy replicas in the gift shop there. Ie.: fake cobs. And humorously, some of those fake cobs have been found on the beaches around there in Florida. Giving md'rs a heart-attack, haha.