Some of them have dates printed on them, but with Australian it can be a bit more confusing, you have to be able to read the signitures and match them up to dates when the people were in office. This is certainly the case with a lot of the modern Australian Polymer notes. This list might help LOL Governor's Governor of the Reserve Bank of Australia Term as Governor Glenn Stevens September 2006 – Ian Macfarlane September 1996 – September 2006 Bernie Fraser September 1989 – September 1996 RA Johnston August 1982 – July 1989 HM Knight July 1975 – August 1982 JG Phillips July 1968 – July 1975 Herbert Coombs January 1960 – July 1968 Governor of the Commonwealth Bank of Australia Term as Governor Herbert Coombs January 1949 – January 1960 HT Armitage July 1941 – December 1948 H Sheehan February 1938 – March 1941 EC Riddle October 1926 – February 1938 J Kell October 1924 – October 1926 DSK Miller June 1912 – June 1923 Secretary to the Treasury Sir Roland Wilson CBE 14 January 1960 28 October 1966 Sir Richard Randall 28 October 1966 31 October 1971 Sir Frederick Wheeler AC CBE 1 November 1971 8 January 1979 John Stone 8 January 1979 14 September 1984 Bernie Fraser 17 September 1984 17 September 1989 Chris Higgins 18 September 1989 6 December 1990 Tony Cole AO 14 February 1991 23 March 1993 Ted Evans AC 10 May 1993 26 April 2001 Ken Henry AC 27 April 2001 You might want to check that the last two named in each office are still there, I have not updated this for a while.
On the polymer notes, it's a lot easier to identify as the first two prefix are the years when the notes are printed.