If I were you, I would contact a GM requesting they check out a potentially duped Item. I wouldn't want to get caught unknowingly with a dupe. In fact people that I know got banned a few years back for the same issues. They purchased a bunch of stuff in bulk and were reselling those items as single items for profits. It wasn't a huge amount of items but apparently they WERE indeed duped by whoever he had purchased them from. Guess who wound up with the ban? You guessed it, my friend who didn't know and was now reselling dupes under no knowledge of his own.
Just do yourself a favor and contact a GM regarding the item, only he/she can tell ( I think) if the item is truly real or a dupe that needs to be turned in to protect your account.
Hope its NOT a dupe, hate to see you lose an item. But I would even more hate to see you return to this forum stating you were banned from the game fro dupes. Good luck and hope turns out in your favor! PLEASE let us know how this turns out!