Wouldn't believe it tbh. That leaker got a lot of things wrong about RDNA3 and then deleted their whole twitter timeline after the launch.Saw that rumour as well, absolutely dreadful if true.
Logically speaking, why would AMD price a midrange GPU at $649? It would not only go against what they've said about their strategy with RDNA4, but it would represent a $150 increase on the 7800XT. I struggle to think of any reason why they wouldn't price it at $499 or lower.