I really didn't like the rust product on the end cover. What a mess it made! At each bolt, the product was flexible and didn't crush well. It just ended up coming off. It looks nice, though. I'll spray it with a satin clear paint to protect the small area of bare metal where the coating came off. I installed the rear cover by using a tiny amount of grease on each shaft shim to hold them in place. I used the gasket and sparingly but carefully applied some Ford Motorcraft TA-31 gray sealant.
The side covers were a different story. I primed them with a 2K epoxy primer and sprayed them with an industrial coating in gloss black.