Probably not at this time, but with open hostilities they would easily be wiped out by missile strikes. After all, they are islands of a sort, targets that don’t move, and locations precisely known. The significance of the fake islands is not military but diplomatic/legal, designed to Validate and expand the Chinese Territorial claims in the Seas between the mainland and the inner ring of islands.
Not to worry; as GW will send all that melted ice to COVER them low-lying ‘islands’.