Hell, even in a wholly established order, they will lie, they will create new official histories. What's "the truth" in a fascist society can change from one day to the next depending on the needs of the ruling fascist order. Hannah Arendt wrote multiple chapters about the way officially recognized truth is manipulated for power in a fascist regime and how folks devoted to that order simply changed stream because there is no "truth" under fascism; only power. Truth is what power can make it.