Curious, why? Why mark the story that says it's from 10 hours ago, with lots of votes, as a dupe, and move comments to a newer story saying it's from 1 hour ago, with only a fraction of votes? Not criticizing, just curious.
The one we moved it to was submitted first, and we try to reward the first submitter of a story. We had to update the timestamp to give it full time on the front page but you should see that the ID is lower.