Ever read Catlin's descriptions of the fair Mandan?
For another tidbit, and I think this is my own original observation, some of the Aztec pictures of their ancestors show them as having wavy or curly hair.
Read this, you'll like it.
Btw, Thomas Jefferson told Lewis & Clark when they were reporting on their trip through the west that he didn't want to hear anything about blue-eyed Indians.
There was a fear that other European nations could/would make a claim to the western regions of North America.