It would probably be a good idea to check what (if any) substructure the ladder support attaches to and repair that as needed so that the ladder mount isn't weakened. It may very well just be the fiberglass that it attaches to, or fiberglass with a backing/spreader plate, in which case the diamond plate repair should be more than sufficiently strong for the job.
I would check and recaulk if needed the other ladder attachment points. It's possible that some of the caulking may have been moved enough to crack or pull away.
