Gauche appears to get his memory back, though all his confirmed memories relate to events regarding Lag or things Lag knew. As a result, Dr. Thunderbird is concerned that, if Noir is still in control, he could potentially pull off enough of a deception as to pass off as Gauche. This possibility is further made possible by the fact that Gauche suddenly disappears, though that could also be due to Roda suddenly appearing again, and perhaps kidnapping Gauche. As it turns out, Dr. Thunderbird’s fears are true as it was merely Noir posing as Gauche.
However, Lawrence still seemed concerned that Noir wasn’t on their side anymore, so he sent out people to eliminate Noir, so things have become more complicated as Gauche/Noir may not really be on anyone’s side now. One doesn’t know if this is due to Gauche and Noir having some battle within Gauche, or whether he was Noir all along, or what.
It does seem like Noir had lost Gauche’s memories, so it’s not like Gauche was pretending to be Noir, though I suppose that’s a possibility now if Gauche has Noir’s memories and came to sympathize with his goals. Gauche also told Lag that he was sorry he didn’t look into what happened to his mother. But what if he did, and that’s why all of this is happening now? I guess we’ll find out soon.