The dating reveals the text to have been written between AD568 and 645, while the dates of Mohammeds life are traditionally given as AD570 to 632. This means that at the very latest it was written before the first formal texts were supposed to have been collated, and at the earliest it was written before or shortly after Mohammed was born.
Doesn't carbon dating have a margin of error that can spam decades? I wouldn't get that excited about this prediction to be honest but of course the media will have a field day with it. Just like the bible it probably have nothing to do with the people who they claim wrote it nor is it obviously an acurate text any way (much like the bible).