If the inner mounting plate is loose you would have to open the inner cowl to weld it, there is no access to that area without removing and rewelding panels. The plate can be reattached with J-B Weld but you need to mark it and clamp it while it dries. I believe these were actually pressed on by the factory and they do come loose every so often. Good luck.
https://www.flickr.com/photos/advance-design_parts_co/12647382934/in/album-72157641244124604/