I am an Original AOL Legends Player, I remember that Amulet from event long ago, it was a legends only event and It was definately released before the end of season 3.
Again, I dont remember all the details, but I remember the Item, because had made a Dark Elf thief at the time, and I wanted the necklace for my Thief...
I am sorry, I do not remember how many were released, or the Exact event... but it was definately a Legends event item, and the event was before the start of season 4...