That sounds like enough time to me. I am assuming that SA will not through check your luggage so you will have to pass through immigration, retrieve your luggage and check in again.

But I have no idea how busy arrival immigration is at that time. (I invariably arrive in the morning. Maybe others with experience at that time could chime in.) Departing immigration can be a real zoo around then though it normally subsides by around 8pm. And as long as you are checked in it is very unlikely you will not make it on board.

So I'd be inclined to go for it - but knowing there are no guarantees especially if your inbound flight is delayed. I'd check the stats on that too just to make sure it isn't a chronically delayed route.