I stand corrected, but I do believe SAA still operate aircraft from their preservation fleet, in fact, I saw an ad in the newspaper a few days ago, where a flight was advertised on a SAA Skymaster from CPT to George, overnight and return the next day, at something like R1400.00 pp-not bad. They also advertised a day flight around CPT, so yes, they obviously still fly them. E-mail SAA for details (don't hold your breath though) or go through ACSA (Airports Company South Africa) they are always very helpful.
Spotting at CPT: viewing platform is a closed balcony inside the building, rather small, and can get annoying if there are many people. In general CPT is not the best place for viewing, although you might get some good pictures during dis-embarcation and boarding as the airport does not yet have jet-bridges, so you'll be walking airside (bridges on line in mid 2002 I think) If you are flying through JIA, it might get better. Joburg airport is being re-developed at a staggering pace, it is HUGE, and I think it offers far better viewing chances than CPT. Visit the ACSA homepage for airport details. Maybe you can contact the Good Hope Flying School-based at CPT International, I'm sure they will be more than helpful in giving you some further info. If you fancy a flight in a 1960s British fighter plane, contact Thunder City, also at CPT airport-owned by some nutty British millionaire, and the fighter jet is I think the only one still flying-perfectly safe though!
By December SAA should have phased out all Airbus jets (A300, A320) from the fleet. Leaving a domestic and regional fleet comprising of B732/8. Chances are pretty good you will end up on a B737-800.
Hope this helps a bit-enjoy