Yes, the huts can be booked in advance.
They set an online tool for this purpose, which is available at : www.welcome-to-oze.com/reserve
You can also reach this page from the main page : www.welcome-to-oze.com
by selecting the green icon on the right of the icons menu...
I highly recommend that area, which is simply amazing. I however have never overnighted there, so I can not comment on the accommodations.