Closet Bolt on Drain Assembly Advice Needed

I am finishing a shower pan installation and had to replace the drain closet bolts. This is a slip tight type of drain assembly. It is on a second story. I used closet bolts with bonded neoprene washers. Do I need to use silicone or anything on top of the bolts prior to putting the pan down on top. Is is likely that water can get by a neoprene washser and through the threads down to the story below? I cinched the bolts down tight. It will be covered for the life of the shower pan so I would hate to have to pull it apart because of a leaky bolt?? The guy that did it before used a asphalt type of emulsion which actually ate the underside of the neoprene washers that were in there. That was not good!