Unfortunately this disregard for important archaeological or historical sites is not limited to the Palestinians--many countries are guilty of it. It is a struggle in the United States to preserve Revolutionary War or Civil War battlefields from development.
The clue was Bronze Age. Philistines had iron.
There's been no scientific dating of Narmer, per se. The only way to get that would be to try some sort of radiometric dating on the Narmer palette, literally his only unambiguous monument. The RC dating on human hair samples proved to be about 800 years before the Great Pyramid, so 1000 (the old date) is definitely in the ballpark, at least. There's no apparent connectino between Narmer and Aha et al, and the Egyptians referred to their supposed founder as Min (Menes), a name also attested from at least one Akkadian record. It seems likely that Egypt made a big deal about the unity and the two crowns precisely because Egyptian unification was unuaual. Menkaure, grandson of Khufu, was succeeded by his son, apparently, but the son is assigned to the 5th dynasty, and reverted to building mastabas on a site south of Giza.