Well, sage wall looks like stonework to me. I do not look down on the people who came before us as incapable of doing large stonework, but it would be neccessary (as several have stated above) to do some excavation for additional information. Discarded Iron tools? Broken Pottery from the Stone masons? Bones telling us what they ate? Skeletons from the people who lived and died on the site?
I think that there was also stonework high in the Andies looking down at the Amazon basin about which we know nothing.
I’m more interested in that he could move and position blocks of those sizes by himself, with only ancient techniques available to him. It also suggests, possibly, that that the number that built the pyramids may not have been as numerous as we have been led to believe or perhaps they were built quicker than it was thought.