Been some time since I've read Uncanny X-Force. I thought he was a clone who was given false memories to think he was some dude who purposely underwent treatment.
Either way, even if he isn't an exact clone of Arkady (ie from his DNA) he is still someone who has Arkady's abilities and isn't Arkady thus he is in a sense a clone. I hope that made sense.
Hopefully someone else can shed some light on this.