Yep, I owned the first two Osibisa Lps. And don't discount Paul Simon's Graceland (only LP I can stand of his ;-)).
Here are some more S. African artists I enjoy. These all have labels from record stores in S. Africa. Kind of neat.
Chris McGregor's Brotherhood of Breath, Country Cooking and Procession
Sipho Mabuse, Chant of the Marching
Winston Mankunku, Jika
and this on really grabs me
Chris McGregor, Louis Moholo, and Dudu Pukwana, Blue Notes for Johnny