Bung for door lock maintenance hole

From model year 1967 is a special opening made in the door exactly at the right height of the lock mechanism and is completed with a white plastic cover. This special opening was made for lubrication of the door lock mechanism, not many know this and therefore never lubricate the door lock mechanisms, a few drops of oil at every maintenance schedule, ensures the mechanism works smoothly; don’t forget to cover the hole with this bung