I believe some had a copper head gasket and some didn't, you would need to sit the head on the barrel and see if there is a tiny gap, or measure the liner height verses the head spigot and go from there. On this Comet I am doing I just used a fine bead of sealant at the base of the barrel to seal it into the top mouth of the crank case. I also went to a fair bit of trouble to re-possition the oil feed hole to the rear of the piston skirt, as the standard "Double hole feed" was too high and would be injecting oil into the rings. Pretty important if you don't want a smokey engine.