<<only explanation for cocaine would be a South American source as early as 1000BC>>

Your statement speaks for itself. Now it must be possible IF there are traces of cocaine to determine the genetic similarities of either. they either are or are not.

If not similar it would still be interesting as regards the cocaine being in Africa homegrown.

i would point out that humans have not changed much over the many millenia. Today celebrities,artists,politicians and what evere go over the top with things like cocaine and hallucigens. Why expect an Egyptian king NOT to use it if it were available. And tobacco as well.