Yes I opened it and there are no screws like the lights down below. These appear to have studs coming up with a pressed on washer which cannot be removed without damaging it. And there is really no access behind from inside the RV. I am considering pulling them off and gluing new ones on with liquid nails.
They may have been put in with pop rivets. Just drill out the old one and use a new one to install the new one. You will probably find that the ground connection is the real problem for not lighting and you will still need a good ground on the new ones. You will need a wire for the ground also since fiber glass does not conduct electicity.
2003 Newmar Mountain Aire, Workhorse W22, 2008 Saturn Vue, Falcon 5250, & US Gear Unified Tow Brake
Update, I decided not to remove the assemblies because I was afraid of some screw dropping down inside where I could never retrieve it. The rivet studs are the + volt and ground, so I wrapped a piece of wire around the rivet stud and secured it with a nut that self-threaded itself enough to hold. The other bare wire end I stuck into the socket and insterted the bulb to make direct contact with it. That was the + voltage side. I was going to do the same thing on the ground side, but I found that sticking some foil in between where there was a joint helped make the ground contact tighter at the stud and then the bulb lit fine. Oh, the middle three lights really cannot be accessed from a ladder, so I did it by laying on the roof and hanging over head first. Yikes.