Seventh...I think you got the meaning of that estimation all wrong...
it´s not because Gautengaz are not that informed, it´s because most of us are not originally from GP. Take Mandela, Sisulu hell every polotician for that matter. they all have residence in GP, and they resided here for most of their lives. The Apartheid regime deported anyone and everyone from GP (i.e Transvaal), if you spoke Xhosa Ciskei/Transkei you went, Zulu Natal was your home, and so on and so forth even if you were not originally from these areas.
now that´s out the way, origin of hihop in SA? well no one can claim they know where it started not even us GP. The thing is most things develop simultanously in different places, and due to the lack of information on it people will think they are the first, when in essence they are not. f*** where it started, it´s won´t change a thing. One thing about GP, we´ve got hype no one can dispute that. When GP does something it does it BIG...hence some ignorant fools think everything starts in GP.