Yeah, it's early days for this hypothesis (and the authors are actively engaging the broader scientific community to test the hypothesis... as it should be) so fershure, skepticism is required.
If it turns out to be "true" (as true as scientific observations can be) it sure would be a big deal.
It would also jibe a little better with the protestations of many native american groups who denounce the current theories on how they arrived (by which I mean they believe they've been here WAY longer than current archeological consensus states).
Just interesting stuff to me and I recently found out Steve-O is into this type of crud as well.