Yes - days old fledglings have pink knees and spend a lot of time chewing lose skin on their feet - they also may have white rather than grey beaks your image shows a whitish beak but I thought this was a trick of the light so i was just checking for other signs. A very young fledgling strongly suggests that nesting occurred nearby
On my return one gang gang was calling and I could hear a return call from the forest above the road. Bird was in a large gum behind wattles in the grounds. Don’t know tree species, but got a sense of mature but not old tree. If nest there could account for anecdotal sightings of many gang gangs At AR. Also numerous older gums in forest with hollows. Next time I go, not till autumn, I’ll check under tree for wood chips and/or holes