Apart from Oakland Tribune at one point writing about that the US government was selling drugs to fund arms in other countries, I don't think the whole "selling crack to poor" thing has been factually proven (yet).

That doesn't take away the fact that they sold weapons to an embargoed country in order to fund right-wing paramilitaries, which is horrible in it's own, but drugs doesn't seem to have been involved as we're seeing with The War on Drugs.