Probably not "pressed into service". The Aussies never switched to No. 4 Rifles and only ever used No. 1's. If it's Brit, it was probably issued to an Australian unit during W.W. I. Aussies got 'em in Africa. Should still have the manufacturer and date on the butt socket. It have any 'FTR' stamps on it?
"...early years of WW2..." 1942 was not the early years of W.W. II. W.W. II started in 1939.