The rails, where the barrel locks into the slide, and a little where the bushing and barrel meet is all you need.
Wipe external oil, shoot, clean, reapply.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)