I was wondering about that, too. The locals didn’t have any sea-going. I don’t think they they even had anything like the giant whaling canoes used in the Pacific Northwest. Why would they have a seaport?
Also, there are supposedly wreck sites in South America with Greco-Roman type amphora. I think somebody was trading in South America loooooooong before Columbus or even Leif Ericson made it to the western hemisphere.
Where they Greco-Roman amphora, or were the Phoenecian/Sea People amphora? Around a thousand years difference, and the later puts it around the time of the rise of the Olmecs.