The introduction of the 6 star standard was on 1st May, 2011 and the 5 star introduction was (I think) about or possibly/probably the same time in 2005.
The installation shown would be compliant with both the 5 star and the 6 star standard provided the house also had a solar HWS fitted or the property was connected to recycled water. If no solar HWS was fitted or the property was not connected to recycled water, then the installation shown is not compliant in either 1 of 2 areas. It is not uncommon and I wouldn't be happy with the installation regardless.