I say no. 4/15 is the start of the Guangzhou Fair. One of the highest demands for tickets to HKG. BF is sold out for 4/17. And for 4/14-16, they're only selling "D" class for >$8,500 r/t, no J or Z. For 4/13-16, fewer than 10 open seats on each flight when viewing the seat map.

But yes, it is possible to get confirmed upgrade at ticketing. Very very rare, however.