It’s a big galaxy torn between two superpowers, so yeah, why wouldn’t the story of “guerrilla” soldiers three decades ago be history somewhere, legend somewhere else, and just plain propaganda lies in other places.
Also if you lived on a junk planet and some old guy told you the tale of the young farm boy turned wizard-warrior who helped take down the Galactic Empire, would you have believed him? You’d probably take these stories as legends, folktales, or at the very least apocryphal re-tellings of history. Also doubt Jakku had history books. Maybe Hosnian Prime, but not Jakku.