Silicone? It should have rubber bushings/gaskets placed between the tank and bulkhead. If you add silicone to that setup, first the gasket will for sure leak where air is trapped and the silicone will also eat away at the rubber gasket. I would not use silicone at all if you have the gaskets.
Not all bulkhead gaskets are made of rubber. If you have rubber gaskets, then you probally have a sch. 80 bulkhead, which is gray in color. Most sch. 40 bulkheads have a gasket which is made of some kind of soft plastic, which will most likely leak unless you run a bead of silicone between it and the tank.




