At least for South Africa the 3rd party insurance for government property is officially included in teh fuel price. Dunno about NAM. I traveled around SA, NAM, BOT and LES with a german rego and had no local insurance whatsoever, because my german insurance agent told me that my european insurance covers 3rd party damages in foreign countries as well. Not sure whether that would have happened in the "worst case"
But what you should consider is an insurance for your own vehicle, as most drivers in Africa are under insured...
Only when we pause to wonder
do we go beyond the limits of our little lives.