If there are differences between OJU and OJA therefore I would grateful if you could let me know what they are
VH-OJA - VH-OJQ Had No Taxi Light
VH-OJS - VH-OJU Have the Taxi Light
VH-OJA - VH-OJQ Had the Manual NAI Switches
VH-OJS - VH-OJU Have the Auto NAI Switches
VH-OJA - VH-OJQ Had the Electrical Fuel Scavenge System to the Left Wing Main Tank Only
VH-OJS - VH-OJU Have the Hydromechanical Scavenge System to both Wing Main Tanks
Of course if you wanted to fully recreate the flight as it was 'back in the day' you would have to select a Mechanical MCP, disable the GPS Navigation System, TCAS System & select the Mechanical Standby Instruments (with no ILS) & CRT Screens. You would also need to deselect the Gross Weight & SAT Display Option from the EICAS Options under the Warnings Tab in the model preferences. Also disable the the TERR options via the TERR Overide Switch.
I am sure that there are others here who have a much more in depth knowledge if I have missed anything.