VH-OEJ is the youngest 747-400ER in the fleet I believe.
It was the one our Olympians came home on wasn't it? The Red aboriginal arty one.
VH-OEE (the one the pope flew home on?) is another newish 744ER.
The incident aircraft (VH-OJK) is a standard 747-400.
If this was an 747-400ER that hole would be right next to the auxillary fuel tank in the forward cargo that only ERs have.
Flight crew earn every cent they get paid.