Yes, Bullet, Ralph, Zero and Fixit were X6's and an X6 being about 16 would seem to fit the ages they appeared to be on the show.
Sketchy: "At least Normal knows who he is."
O.C.: "A constipated, crusty, angry, rhythm-free, Republican white man?"
I'm going to be me, so it you can't stand me, sit down...If you can't face me turn around!