Pardon, but that statement is against all logic: If all reports say - just look at page one of this tread - Block III is still in development, why should then an image that is a few months old and showing a prototype be a proof for a Block III??
We know images of the Y-20 prototypes at Xi'an that are there longer than 12-18 months ... are they proof that they are already testing the WS-20??
Come on guys, I can fully understand your high hopes but you should stay realistic. Unless a true insider does not tell a Block III prototype is already manufactured - and so far all reliable sources say exactly the contrary - there's no reason to believe this is a Block III.
Often the most simply answer to an unconfirmed issue is the correct one ... so IMO it's just a B.