During the first skirmish when Scott gets shot, the lieutenant shouts for the 203 (grenade launcher), someone answers that Mick has it and Mick is behind him. However Bill in the forward position doing the firing clearly has the 203 attached to his rifle.
In the final scene of the film, when Harry and Bill have flown home to Australia they sit in a bar and have a beer. Through the window the Sydney skyline can clearly be seen in the distance. However, the Australian SAS are based in Perth, not Sydney and it would have been to Perth that they would have been flown home to.
When notice of their leave is posted, the PA mentions Newcombe and Orantes. These are two tennis players: John Newcombe of Australia and Manuel Orantes of Spain. Newcombe and Orantes only played each other once - in 1973 (which was after the Australians had withdrawn from Vietnam and long after the SAS had withdrawn - October 1971). During their careers, Newcombe won 7 grand slams, whilst Orantes won one.
Just before the last skirmish scene Bill and Harry observe what is supposed to be a convoy of helicopters en-route to battle. However it's quite obvious that there are really only two Huey's and one Chinook. Some slicker editing or directing could easily turn those three helicopters into a convoy resembling as many helicopters as the director required.