I agree that the fact that it might be during the lifetime of Mohammed is amazing. That should be the headline.
On the other hand, I know that Muslims believe that Mohammed received the Quran after a visit to heaven, and I know that non-Muslim scholars instead claim a 'genesis' from Judaeo-Christian traditions. As a non Muslim, I am more inclined to the latter, but to suggest that a C14 date 'suggests' that the manuscript pre-dates Mohammed is simply headline-grabbing rather than serious historical/archaeological research. Now if the C14 date had given a range wholly before Mohammed, that would have been a story!
PS I don't think Keith Small is a professor! A quick bit of research suggest that he's a Manuscript Consultant to the Bodleian Library at Oxford University.