Your Tail Lights
If you search for a thread on this issue you will find many comments, many pictures on replacing what you have with the Command Electronics LED lights. Even when you get the new LED lens you will get the same piece of garbage foam gasket. Many of us threw it in the trash and then use a roll of butyl rubber as a gasket and rubber O-rings with new stainless steel screws. Then, once installed, get some good RV all weather caulking around the outside of the fixture. Do tell Command Electronics that you have a Thor and they will get you the ones with the plugs that are ready to plug and play.