If the manuscript were a century earlier at the very latest, sure, that would start the search for some answers. But the date ranges mesh well with traditional Islamic dating, so there's not really a conflict here. I suspect some poor academic has been asked a question, answered it honestly, and the story has taken off. If the early end of the date range is correct, yes, interesting questions. But the tests weren't saying that one has to take the earlier dates as being more likely than the later.
Not really proof of anything, although the ideas on the origins of Islam and its writings are interesting in themselves.