The South African Reconnaissance Car was, like it's name seems to indicate, was a reconnaissance vehicle. The original armament of one Boys rifle and one machine gun was considered inadequate by the British and the modified their Marmon-Herrington (like they called it) to carry various different weapons, including 20 mm autocannons. I have not heard that it would ever be used as an AA vehicle. This, of course, doesn't mean that you couldn't do that in FH2.