I haven't heard of the creationist alien theories, but the fact that ancients in south america didn't have the laser or weight lifting technology to create some of their fine cut stones, could lead one to believe they had extra terrestrial help.
Or perhaps they had ancient tech we aren't yet aware of.
Well, PiMPle thinks a guy built a huge boat 47000 years before that so yeah maybe ET showed the Mayans how to call the interstellar Home Depot? Sounds like a reasonable hypothesis. LOL