Like Merrell I looked through these links and saw nothing about the date in a Peruvian mummy. Do you have a source for it?
At one time at my site we had a listing of over 100 African plants that could produce a cocaine type reading ... I will try to locate it. Also you might find this of interest:
"The natural distribution of tobacco is limited to parts of North and South America, Australia, a few South Pacific islands, and one species in Namibia, Africa." From here. It should also be noted that in the past tobacco sprays were used on mummies for control of bug infestations.
They who would give up an essential liberty for temporary security, deserve neither liberty or security -- Benjamin Franklin