You know, this is rather tricky.
At this point there are SO many rares or 'one of so and so many' items out that keeping track of them for the casual or 'regular' player it is daunting. I have rares, I have sold rares, but I am FAR from a rares expert.
Many have possession of 'duped' items while having NO clue that they are, indeed, duped. The UO team pretty much intends players to go to the internet and HOPE they can find reference to an item. Not all players use stratics, and not all players have scoured over the rares list on the rares forum.
I myself came into possession of an item that I was sold and told it was one of a limited number, not a singular item. So, seeing it as a great find, I purchased it. Should I have to reference and google every single item in game? I was only later told by a friend of the history of said item.
It is a lot to ask players that they should just automatically know what is a dupe from not a dupe, or have to search over the internet to see if something is permissible to have in game. IMO the dev team, if they are aware of the issue, should take steps AS SOON AS THEY ARE AWARE THERE IS AN ISSUE. Otherwise, the regular players are then getting suckered into something that is deemed less than possibly legal by the game.
Again, we shouldn't have to scour all over the place looking for answers the team itself should be making us aware of in the first place. Their lack of being proactive then sets a precedent and players (like in this instance, myself) will be obtaining these things and paying good amounts of legally obtained gold to purchase, only to be possibly penalized in the future.
Feel free to disagree, I'm sure many will say 'you bought it, your problem'. But its more than that. Again, I shouldn't have to worry about EVERY in game rares transaction I do or read up on its history. The UO team should be taking the proper steps as soon as a problem is noticed.