Hello. Australian here. I know a bit about this deal, but some I can not (legally) disclose.
What I CAN say is that NIOA are currently AU's largest MIL/LE supplier. They sell to civilians, but majority of their industry is MIL.
As for short term, NOTHING will change. It's business as usual, same products, same management, same employees (with some shuffling).
Some production will relocate to AU (bolt rifles, nothing MIL used).
If you look up how the Aussie supply contracts work for govt->MIL, it makes sense. American made, can supply US entities, Aussie owned, can supply AU entities.
Think CZ-USA, or Beretta, etc... It's a "partnership". Countries usually require their gear to be made IN COUNTRY.. nightforce is a wholy owned Aussie company. NOT USA owned.. it's just a manuf plant.