Yeah it's the same strain shared many years ago by African Herbman with several different people, TSCo offered already several interesting Durban hybrids in the past too... but it came from modern bagseed scored by Herbman at South Africa, not really 70s or oldschool genetics like Sam's one for example. Are you sure the info was about this one and not some of the strains that USC sells through TSCo nowadays?
Anyway African Herbman was collecting and preserving different african bagseeds at the time. Swazi, Durban, something else that he bought as Congo Black and so on (although this one didn't really look like a traditional congolese purebred), it's still possible to find that info here at the forums. Some were interesting, others not so much, just like any bagseeds. That's why sometimes is easier to look for old farmers or preservationists in order to find selected genetics.
This are the original Durban Poison pics that African Herbman posted a decade ago:
https://www.icmag.com/ic/showpost.php?p=1135576&postcount=2
CBG's South African was bagseeds from Cape Town as well, so either it could be Durban, Swazi or anything like that. Normally Durban Poison weed came packaged in what they used to call "durban sticks", while malawi came in cobs and others as Swazi came as matchbox weed. Traditional Durban, Malawi Gold and Swazi packaging forms can be seen here:
View Image
What happens in South Africa is similar to Mexico or any other big Cannabis producer. Plus the country simply became a hot spot for the African cannabis market. Many of the african weed is exported through South Africa all over the continent and even towards Europe. The demand for weed in South Africa is so big that they even buy weed from most neighbouring countries like Swaziland, Namibia, Malawi, Lesotho and so on. So i'm looking at South Africa more as a big melting pot of african genetics, rather than the home of the Durban Poison.
Notice that South Africa is the first Cannabis producer in the continent, this is an old graph from the UNODC report but it gives a good idea about the situation. Unfortunately, few African countries have replied the Cannabis surveys in order to keep publishing the UNODC's Cannabis reports worldwide:
View Image
Even what we know as the original Durban Poison from Sam Skunkman was south african bagseeds shared by Mel Frank. Then this Durban Poison and Durban X Skunk hybrids were sold to most dutch seedbanks, the rest is history. But let's keep in mind that Durban Poison is more like a generic name, just like Colombian Red, Oaxacan Gold or Vietnam Black. There are literally hundreds of traditional cultivars all over those places. The thing is finding a good representation or something close to what you are looking for among them.
Anyway I've found this Durban was pretty simiar to the Swazi Red by Afropips in overall terms of high, structure or even terpenes. Classic South African dagga plants.