Originally Posted by Arawn Fenn
That's already consistent with Origins, where he willingly underwent the process. Origins and X2 are supposed to be in the same continuity, meaning that we don't need something in DOFP to explain that line from X2. Even if DOFP changes the past of the timeline, that change hadn't happened yet from the POV of X2 so the X2 line refers to the continuity before the change.
Does he really need the metal claws in 1973? I imagine they could be somewhat useful against Sentinels in the future, but who or what is he going to go up against in the past?
He only volunteered in origins because of a lie. Here he would know the consequences and pain going down this path would bring but chooses it anyway.