He also lied and spread false intel to the Rebels that Death Star 2.0 wasn’t operational. And then he started boasting to Luke that “I lied! We’re up and running! *pew pew pew*!”

Yeah, it would have to be new dialogue. Although I don’t know if any lines like that already exist.

EDIT: I guess, yeah, it doesn’t change the internal journey Rey goes on to renounce the Dark Side; but I feel like I’d still be a little disappointed, as an audience member, if I just watched all of that and then Palps was like, “Ha! Psych!” A good twist should recontextualize everything we’ve already seen, and I’m not sure that this one would.