【How-to】Where does mandalorian fit in the star wars timeline

Vader never told R2-D2 he was Anakin. So unless R2D2 like to speculate or do random guesswork, it doesn’t know that Vader was Anakin. The back-story wasn’t written at that point, but overall, R2 didn’t know. Nobody ever knew he was Darth Vader except Palpatine, the Trade Federation, Yoda, and Obi-wan….