Yeah, spotted that mate - not sure what to make of it.
After It was drawn to my attention that the earliest Automatic advertisement from the Canberra times stated "order now", I did a little more digging to find a sale date that confirmed Automatics were in-stock, and came up with these:
19 Sep 1957 - Nepean Times
03 Oct 1957 - The Canberra Times
So we can be sure that the Automatic was at the very least available for pre-order on the 24th of August, it was certainly in store in both Sydney by the 19th of September and Canbberra by the 3rd of October. The chronology is starting to come together..