All Threaded Fasteners must be lubricated. Oil grease doesn't matter.
All Threaded Fasteners on cars come from the factory with a coating, which is a lubricant. It's not oily, because assembly would be slow down, but that green coating on all Fasteners is a lubricant.I have never stripped fastener, or had it come loose after I have lubricated it and torqued it to spec.