Judging from that, given a means of travel to the North American continent, inhabitence by early human is possible..
Next question is, why isn't there more evidence of their existence ?
If conditions were good, ( hunting, etc..) then such a population, even a small one, would have thrived and grown..
Thus, there should be ample evidence of pre-glacial habitation..
I'll have to take this one with a grain of salt..
Possible, but not likely..