It turns out that this historical revisionism has a long history - at least to 1921.
This book, quoting an out of print Yehoshua Porath book, says:
In an open letter to Winston Churchill on 16 March 1921, the Palestinian newspaper clearly stated: "The first to settle in Palestine in the earliest antiquity were none other than the Amalekite Arabs, our early ancestors."It goes on to say
However, in official reports, the Palestinians admitted that Arabs had only settled in Palestine since the Muslim conquest in 634.This was not an isolated incident. Here is a 1970 description of an annotated edition of the Protocols of the Elders of Zion published in Arabic in 1967 that makes the same point:
Well, they sure act like Amalekites!
(h/t EG)