Hi!
...It's not panel lines! It's panels!
The fuselage is covered with many (must be hundreds) pieces of Oracover, first wet sanded on a piece of glass, then put on with a covering iron. The upper side of the wing is also covered with several pieces of Oracover chrome. Every piece of film is wet sanded in different directions to obtain a well worn finish.
The engine nacelles and some other difficult-to-cover-areas are covered with aluminum duct tape, also wet sanded prior to being put into place.