"I was studied as a tactical attack fighter by my country's Air Force as late as 1980."
I doubt a DC-3 (AC47) could be considered by any strech of the imagination to be a 'tactical attack fighter'. LOL
WWII Lineage; with the caveat of having been flown by many of the worlds air forces would let out the uber-Piper... hmmmm
So.. that leaves the BT2D-1, flown in 1944:
Here's what they looked like in the 70's when the last of 'em rolled off the production line.
I think yer right Ammo. Looks like a Skyraider to me.

Since I'm only a few blocks from what used to be Republic/Fairchild, and since I cried real tears when the jigs and fixtures fer the A10 Warthog were scrapped, I'd say the Aussies were probably lookin at McDonnel/Douglas for quotes on lighting up Skyraider production.. since McDonnel/Douglas at that time still had the jigs and fixtures for the A1's in hand.
My best guess anyway.

Hang