African Blackwood (dalbergia melanoxylon) is classified as a rosewood as it's Dalbergia designation implies. It's therefore newly listed as of 2017 in the CITES appendix II and subject to appendix II regulations. It's rated by the IUCN as near-threatened. It's a super-dense, super-hard and super-stable wood primarily used for wind instruments and turned woodcraft. As far as I know, small blanks are not rare but big straight pieces like one-piece guitar neck blanks are virtually impossible to find. The tree is small and crooked, grows very slowly.
As for the CITES stuff. Guitars made before 2017 with AFBW or any rosewood except Brazilian RW, would be pre-convention to the 2017 rosewood regulations.
Since 2017 started, any rosewood guitar regardless of when it's made would require an export permit from the respective governments to leave its current country of residence.
A pre-convention guitar would be easily granted an export permit, regardless of which country the guitar sits in. It gets a free-pass so to speak but you still need to obtain the papers.
A post-convention PRS Maryland made guitar (made 2017 and onwards), if sitting outside the US, would require the original export permit which allowed it to leave the US, in order to obtain an export permit to leave the current country of residence. For PRS to ship it to the international dealer in the first place, they would have obtained an export permit leaving US, so its not a problem to obtain that copy from the dealer. No problem.
If the Maryland made guitar is sitting in the US with a US dealer, PRS would not have obtained an export permit cos it never left the US in the first place. If you bought the guitar and want to ship it out of the US, you'd have a problem. You'd need the export permit that allowed the raw timber to leave India, Madagascar, Honduras etc for the PRS Maryland factory. You'd never obtain that retrospectively, I believe, no matter how many times you contact PRS customer service. So, post-convention Maryland made PRS guitars with rosewood that were meant for distribution within the US, will forever have to stay in the US.
Sorry, it's horribly complicated I know. It's headache inducing to write and read.