The problem with cork gaskets is that they are easy to over tighten. I got my hand slapped and my ego bruised went my first boss in aviation caught me tightening valve cover gaskets on a Lycoming with an open end wrench on hex flats of my screw driver. I always remembered, after that, too much torque is a bad thing.
Too much silicone on the inner side of the gasket can break off and clog grease passages. I think he meant wheel bearing grease. It keeps the gasket in place while tightening up the fasteners.
Old Crisco lard works well too. I like to use old Crisco to hold small, hard to start nuts on my finger tip, when there is no room for two fingers. Harder on your finger's skin, but a more modern practice is super glue the nut to your finger tip.
hugs, Brandi