>>7944785This isn't even a Disney thing, the EU had A-Wings before ANH in several places. When someone realized this clashed with the idea of Dodonna having come up with them after Yavin, they had to retcon the earlier versions into being the technically different but visually identical R-22 Spearhead.
Hell, the original vintage A-Wing ended up being released as a tie-in to Droids, a show that took place before ANH.