Good rule of thumb for installation of all o-rings and lip seals is to apply a smear of the fluid the seal or o-ring is sealing on the sealing surface. A lot of seals and o-rings are composed of material to work with the fluid it's sealing and applying some kind of lubricant that's not similar to the fluid being sealed, may ruin the seal.
If installing a lip seal and the casing of the seal is metallic, you can apply a smear of silicone based engine assembly sealant to the lip seal outer case and then install the seal. If you put any sealant on the bore that the seal will be installed into, as the seal is installed, it will push that sealant ahead of it and cause a build up of sealant inside of the engine that can break off and end up in the engine sump. Hence a lot of members pulling the sump and finding silicone jammed up in the oil pick up screen. That is completely accountable from poor maintenance activities such as what I just described.
