Don't be so sure. If you read to the next page of the thread, you'll notice that Byrne comments "Okay, back to 'stardates are not chronological!'" when somebody points out that his latest story would have to take place before "Space Seed." I think the numerical list of stardates is just him examining the various possibilities. Yeah, but he was kind of coy about it. He never had the Borg identified by name in the story, and just included a clue at the end to help the reader identify them, but not Kirk & crew. I remember Byrne said he was concerned that CBS/Paramount might reject the story for conflicting with some point of TNG/VOY continuity, but to his surprise it sailed through.