I replaced the offending fastener that I discovered and showed in the first post of this thread with a bolt washers and a nut. I attached them to the same point on the existing metal bracket. Thought I was good to go.
Well, I crawled under the RV after our recent 2500 mile trip, and found this:
Apparently the metal bracket chose to depart the vehicle at some point in the trip and now I have a shredded mud flap. It’s not of much use now.