Yes you are correct in the mounting. Your top picture goes on first. DMT makes a kit for the installation. A thin piece of sticky tape rubber goes on first, it is sticky on one sede,then your top molding screws in place, then a foam gasket goes in between the two chromes, then the chrome. The kit is like 22 bucks. It keeps the water and elements out. Then your rubber seal just pushes in the second chrome. It takes about 13 screws to do one side. Use the flat headed screws on the first chrome molding and the round on the second. Dont over tighten the screws or you'll strip them out. Stick the rubber gasket to the lip rail and not the chrome and place it where you can see your screw holes. The second foam you can glue to the top of it and then install.
DMT is Detroit Muscle technology