It does. We probably changed the url of the other thread; I don't remember (there have been so many), but we usually add a comment indicating what we did.
On the other hand, the duplicate detector is also quite porous—in most cases a slightly different URL will get through. That's by design: we want the best stories to have multiple cracks at the bat. It's easy to abuse, of course, so we ask people not to abuse it. A small number of reposts is ok.
