It's a good idea, to wipe the steel/iron parts down with an oily rag/cloth after cleaning.
Even the old/tough Parkerizing used on US military weapons needs some oil on the surface of it to help keep it from rusting.
I'm not sure that oiling a cerakote finish does much good, but I do it anyway. Sooner or later it'll wear through somewhere and without some oil on the bare metal wear spots they'll rust.
Rust/corrosion = bad. Bad for appearance, bad for functional reliability, bad for you if you depend on that weapon. I remember my father-in-law saying that semi-autos ran better "dry". I also remember him trading his off every few years for a new deer rifle/pistol when reliability issues or accuracy issues developed.
