I went to Egypt over Christmas break in 1970 while attending the University of Stockholm for my Junior year away from the University of Denver. The so called War of Attrition between Egypt and Israel had just ended in August but there was still a large presence of USSR military in Cairo. Luxor was not a well developed tourist attraction then with really just the one Colonial era hotel which is where we stayed. Ruins of the Karnak temple were basically wide open to visitors to roam around. I don't remember there even being an entrance or having to buy tickets etc. Just walked around freely. It was the same story when I took a little ferry across the river to the burial temples - among them King Tut's on the West Bank of the Nile.