The office of treasurer is not a constitutionally required office at any time. The first swearing in was of O'Farrell as Premier and Stoner as Deputy, that's all. The office of treasuer remained vacant until Baird was sworn in. This was not modelled on Whitlam-Barnard's two-man cabinet nor is it contemporaneous to compare them so. If you read media reports of the time and the NSW Parliament profiles, there is no suggestion that O'Farrell was sworn in as Treasurer. SMH: http://www.smh.com.au/nsw/state-election-2011/barry-ofarrell-sworn-in-as-nsw-premier-20110328-1cclg.html or try NSWParl: http://www.parliament.nsw.gov.au/prod/parlment/members.nsf/0/275291281FA0F28E4A2567450001658A 
 If you want to continue to argue otherwise I suggest you provide some proof. Regards