I agree that making a distinction like "Sub-Saharan" is often unhelpful (like it would be to divide European history entirely by the Alps, say). I think some of this may be quibbling over terms, but my impression is that the Timbuktu manuscripts are all written with Arabic orthography, but in several languages (much like we're happily using the Roman alphabet here!) There are clearly multiple other indigenous scripts native to Africa[1]. Axum and Lalibela are remarkable architecturally, and Timbuktu itself certainly has multi-storied buildings[2].

1: https://en.wikipedia.org/wiki/Writing_systems_of_Africa#Anci...

2: https://en.wikipedia.org/wiki/Architecture_of_Mali