Yeah, the Itinerant Moogles have shown up periodically, previously selling the Bomb, Slime, and Cactuar earrings. And I think maybe something else.

Greater point, tho, is nothing is guaranteed permanently exclusive. And, frankly, if you're putting such a huge amount of significance on having a game item that other people don't, maybe you're taking the game a little too seriously. Other people having items that you have does not have any impact on the game for you. Play the game. Enjoy the game. Quit worrying so much about what other players do or have.