That second picture of wood looks like it has nails in it. Do those nails look ancient? To me they do not. They even have round heads.
Ancient nails could have round heads. The square nails with square heads might be easier to make from plate stock but round nails from wire stock wouldn't be impossible. Some of the tribes in the region were known as excellent metallurgists and kept many trade secrets.
If a nail you're seeing is just a tiny bit below and to the left of dead center, I don't believe that's a nail, but I'm not sure what it is.