Point taken Old-smithy. You ask an axtremely good question. Where Australia manufactured bayonets in the number as per their rifles this was brought about through Government factories unlike the Britishicon who put bayonet production out to commmercial ventures such as Wilkinson, Sanderson and the like. Australianicon production was either at the small arms factory of Lithgow or its main feeder factory for bayonets after 1941 and that being Orange.
Australia did produce "Reserve" supplies of bayonets in the early years and these were usually marked during WW1 on the crossguard with a numeral of 1 to 6 representing the States eg 1 = Queensland, 5 = Western Australia representing as to where they were being held. When reserve supplies were used a stamping of D^D was added above the number and the particular rifle number added to the bayonet at the pommel.
Many Australian bayonets have one or more serial numbers and I have in my possession a 5MD bayonet with three numbers and because of its chemical parkerisation its final refurbishment was during the 1950s (Korean War). Their is also the odd ones like a British manufacture with South Afican issue markings and finally the refurbished markings of Lithgow in WW2.
Irrespective of the original manufacturing date, bayonets were refurbished in the 1940s and are marked as such either on the pommel or ricasso. No new rifle numbers were appended. P1907 bayonets ceased production in 1945 at Lithgow however many were subsequently refurbished and the finish is a dark black chemical parkerisation (dull matt black) and the relevent date appears on the the top of the tang usually in the format of R - Date eg R-56. Again no additional rifle numbers are appended. Rifle numbers around WW2 were only added at production. In trying to match bayonets to rifles there is always more than one approach but deciding on the appropriate one (or more) is always facinating especially for us Aussies.