Quote Originally Posted by Alhanelem View Post
This dialogue exists because people may posess the item from before the system was changed.
Other NPCs are able to have different dialog depending on what the player has done before so that's really not much of an excuse. As far as I can tell, this NPCs dialog doesn't change at all no matter what you do - even if you already have the key item he's selling - which isn't something I'd expect a game NPC to act like.