Is there a particular guideline for items with exactly the same name, published in different books, but with completely different stats/abilities? Is only the last one valid? Can they coexist?
I mean... I understand that some items are reprinted with basically the same purpose but with limitations (i.e. nerfs). In this case i'm talking about completely different mechanics altogether.
Example: "Boots of Sidestepping"
The version of these boots in "Dungeonscape" (p.40) is sweet! You get to do a 5ft step whenever you need to roll for a REF save against a spell or effect - no action needed. If you get out of the area with that move, you don't have to roll the save.
The version in MIC (p. 78) is... i wouldn't say "bad", but it isn't good for it's price (6k). You can do a 5ft. step as a swift action 3/day, even if you already exhausted your move for the round. "Anklets of Translocation" are far superior IMO, and for a fraction of the price (1.4k)!
Even the fluff, describing the item itself, has nothing in common between both books (asides from the fact that it's a pair of boots).
"Dungeonscape" and MIC were printed a month apart, so i'm guessing (hoping) the writters just came up with the same name for different items...