I'm also in Australia and mine turned up without the right cranks like yours. I noticed and they apologised for it.
It took them one week to get the carbon ones on so it may not be a very long delay
Trek Australia might well have known but the LBS literally get the bike and build it. I certainly don't blame them and they were very helpful.
I hope it only takes them a week to get mine in but Trek told me they have no idea how long it will be. I told Trek that my store had been absolutely brilliant as a buying experience. I am more concerned about Treks handling of this. For instance, have you checked everything else on your bike? They have lost my trust because they weren't honest about it all. If they do this with crank arms, what else are they capable of. I know there will be those who would just say, get over it, but my personal response to Trek was to make them aware of how it changed my opinion of them.
Anyway, I look forward to getting the parts on the bike soon, hopefully. Just to be clear, the bike is everything I wanted it to be. This isn't about the bike or crank arms. It's about Trek management and how they treat their customers.