Nothing has changed since my previous answer on 8th Dec. There's no support for Telstra's 850 MHz 3G so coverage would be limited, also for calls & SMS because on many areas there's no 2G. Of course in cities and some towns even on Telstra there would be 2G, possibly still 2100 MHz 3G and in the future LTE support.

EDIT: Telstra has officially shut down the 2100 MHz 3G network it shared with another operator, however it may also have its own 3G sites that could still be active. There are reports even from 2013 that 2100 MHz 3G still works in some places. Whatever the case, coverage would be limited at best.