From their drinks menu, it doesn't look like it.

Mind you, it being the Outback Steakhouse, I'm not surprised. The majority of their stuff has nothing to do with Australia.

And the dessert name "Chocolate Thunder From Down Under" makes all the Aussies I know stare in amazement, before bursting out laughing.
We think the O.S. is extremely entertaining, in its general cluelessness. (They have, at least, stopped referring to the Bloomin' Onion as "an ab-original", which was horrifyingly racist.)