Lube a 5th wheel hitch ?

Lube plate takes care of the friction between king pin plate and 5rv hitch head otherwise that would need grease.

BUT other moving parts of 5vr hitch do require routine maintenance/lubing

Metal to metal contact points, where pivot pints are, pins that allow head to rotate forward/aft and side to side.

I use a spray on dry graphite for the areas inside hitch head and a film of multi-purpose grease on pins that allow hitch movement.

Once a year I disassemble clean/wire brush, repaint and thoroughly lube

No need to if you have the Teflon plate on there but I do lube the pivot points and things like that on the hitch every so often just to be safe.