You need to access the back of the plaque by removing the interior panel behind the driver's side door. I have a '74, which is relatively straightforward. You may need to deal with seat belt h/ware. Once in there, speed nuts/clips hold onto two stems to keep the trim flush against the body. Be careful when you remove the clips - the stems are fairly thin. You may need new clips. If it's rusty in there, you want to clean it and paint it up so it doesn't spread.
