I’m not going to find a source because it would require me to visit those sites. But yes, that is exactly what they think. They call it second migration theory or something like that and it goes a little bit like this: Native Americans came over on the Bering land bridge so when Europeans came over on the Mayflower etc. it wasn’t colonialism it was just more migration!
This theory of course completely ignores that the Bering land bridge may or may not have ever actually been uncovered and that if it was it was about 10,000 years ago while there is ample evidence that the Americas have been populated for well over 50,000 years.
Damnit, that’s what I get for using voice to text.