SAA allows pre-seating based on booking class. Most Y fares cannot preseat until checkin. Expsensive Y and all J can be preseated at booking.
Unless this has recently changed, you can pre-seat all fares on international flights. As far as domestic flights are concerne you are correct, unless you hold Voyager status (Silver is good enough IIRC).
Thanks for having made SAA your carrier of choice - a very wise decision
Depending on your routing and booking class, pre-seating may or may not be available; most of our international routes offer complimentary seat selections at time of booking regardless of booking class, while some domestic routes within South Africa limit the service to certain fares.
As suggested, you should - depending on where your ticket was purchased - be able to access your booking on our website (www.flysaa.com) and use the "Manage my Booking" feature to view seat maps for the flights that qualify.
If you experience difficulties, please give us a call so that one of our agents can assist. If you happen to be in North America, our number is 1-800-722-9675. For other countries, please check flysaa.com for local contact details.