Paulo. I just worked on a brand new jeep just like yours, behind the hinges there is no paint no primer nothing but bare metal, ANY part we took off the car has a mist coat or primer if that , they assemble the jeep complete and primer and paint it, that plus all the foam they spray in the rockers and quarter panels is insane.
We removed the hood bumper and front fender , under the door and hood hinges were rusting bare metal!
This jeep got hit at the dealership by a plow and has 0 km on it and it's rusting, not to mention the bolts were already rusting.
Get that baby oil sprayed , krown will soak in behind all the panels and hinges and bolts and protect it.
Put a piece of Bare metal outside for winter and a piece of bare metal with oil spray on it and you will be shocked in the spring how clean the metal is