DoC,
Certainly not required at the ports they are operating from, assuming they are the only prescribed services operating through the terminal. Not sure what is happening at the Perth end though. If their pax are boarding through terminal with everyone else then then it will be ops normal on the screening front.
The Dubbo ruling in this instance would not occur unless Qantas decided to go back in with their Q400s which I would think is highly unlikely. The airports (councils) concerned would be very unlikely to complicate things any more than they need to. The only downside I can see in all this is there will be no screened transfer. In other words, take the walk of shame out the side gate at Perth and re-check.