FRom what I know about the "new" 6PX, G2X and Z2X the battery tube is glued / fixed to the head. The classic Z44 bezel does not fit.
If you want a Surefire P60 compatible host, you need a 6P, 9P, C2, C3, Z2, Z3, G2 or G3 flashlight body. The 6P bodies should be still available. Other types may be difficuilt to find since they are out of production for more than one year.