Whether a culture is prehistoric has to do with whether they had writing or not. Thus, most of PreColumbian America was prehistoric, while small parts were intermittently literate, even though a good bit of the rest of the Earth had writing. Literacy is diagnostic of whether a culture is prehistoric.
They didn’t have writing in the new world before old world language came? Or just didn’t have Greek or Latin? Symbolism and Hieroglyphs do not count?
https://en.wikipedia.org/wiki/Mesoamerican_writing_systems