What would be the most noticeable consequence if the clock would have been invented in Australia?

The figure 3 on the dial would be on the left and figure 9 on the right !

The arrangement of clockwork and the clockface was dictated by the sundial. In the Northern hemisphere someone facing the Sun sees it apparently moving from left to right. A post stuck into the ground in front of them casts a shadow which moves from right to left, a shadow whose passage can be marked with indicators to show the hour. The semicircle so made is the model for half of a clock dial ; the clockmakers simply copied the movement of the shadow in the movement of the hand of the clock , clockwise rotation.

Down in Australia the Sun appears to move the other way; a clockmaker copying a Southern Hemisphere sundial would have had to set his dial and his clockwork to run the opposite way too.