Yes, this area was burnt badly, but NPWS has just reopened Wollangambe 1 and 2. There is no abseiling, just lots of floating down the river. You will need warm clothing (thermals or wetsuits) and floatation (lilo etc).
You can keep track of park closures here:
http://www.nationalparks.nsw.gov.au/alert/state-alertsYou can also see some of the fire damage from a couple kilometres downstream here:
http://fatcanyoners.org/2013/10/26/bushfire-damage/As you can see, pretty much everything has been burnt down to nearly the water level. The canyon will still be nice, but I'd expect some freshly fallen trees and other debris in there.