The truck has always had a Weber since I've owned it. I just put a new one on. The carbon filter has 3 hoses attached I forget right now but at least one of them just deadends on its way across the firewall into a plastic thingy. Probably a valve. The guy I bought it from removed all of the pollution controls so I have no idea where they should go or what to do with them since there is no pollution control on the thing beyond the ancient CAT which I suspect had been emptied. No I know its been emptied. I've had it off and looked through it. I did remove the hoses and lift the carbon filter out. It smells heavily of gas and was damp to the touch on the bottom exposed filter area. It weighed a couple pounds at least maybe as much as 5. But except for the possibility of the vent line from the tank needing to dump into the carbon filter why would I need it at all?
EDIT- Just to be crystal clear I do not think the canister is the source of the drip. I smelled it wet and put my nose to teh spots on the ground there was no odor. Since the carbon filter smells heavily of gas I'd expect whatever might come out of there to as well.