Ok, so basically, I took a quick look and didn't see anything for this, but I suck at searching so point me the right way if there's something on this.
One of my friend's finally received his copy of the game (the CE) yesterday and installed and registered it today. While inputting his codes his Onion Helm code came back as an already registered code, everything else worked fine as far as I can tell, or at least he said it's only the onion helm code. I told him to contact Square about it but I bet he won't remember for another 2 weeks. I'm curious to know what the good folks here at zam have to say on this. Random freak duplicate code? mistyped the code? (note: I did ask him about the mistyping of the code and he assured me he didn't, though he gets frustrated way too easily and I'm inclined to take this answer with a grain of salt)