Originally Posted by LV2TNDM

Actually, it's Italian threads that could benefit most from a thread-locking compound; they are far more prone to loosening, as the right side cup is not left-hand thread. So a thread locking compound could be in order. However, #242 (blue) would be the way to go. Red Loctite requires heating to something like 475 degrees to loosen, which would fry paint and melt powder coating.
But, that being said, grease almost always is the preferred material, as it's good at displacing water and preventing rust in a very vulnerable spot. The key is proper torque on the cup to keep it in place!