In S3E1, The Rickshank Rickdemption, Rick is shown lying to the aliens via a fake memory. He tricks them into thinking the scribbles on the ground are the secret to interdimensional travel, but it's actually a computer virus. However, when questioned about how he could modify his memories, he says:
True, but you can alter anything you want about a totally fabricated origin story.
Implying that what was shown was fake.
However, when he's talking to Morty at the end of the show, he says:
I'm not driven by avenging my dead family Morty, that was fake. I-I-I'm driven by finding that McNugget sauce, I want that Mulan McNugget sauce Morty, that's my series arc Morty.
I'm not sure what to make of this. Was his family actually killed? Or was he just correcting the fake story he gave to Morty earlier?