I thought about calling Fleetwood but sometimes the mfg route can take a while or even be non-responsive (although I've heard FW is good). Next trip is in 4 - 5 days.
The original top bracket did use a star type rivet. Some rivets "starred out" better than others. The rivet that looks water stained snapped in half. Don't think water caused an Al rivet to snap . . . .
The wall bracket at the back is intact. Yes, it shoulders much of the weight which seems to be in the rear of the unit. There's also 2 screws to keep it from hopping up and off the rear bracket but only 1 screw was installed. Good thing as that screw hole was ripped out in the fall.
The microwave is back in with eight # 12 screws holding the bracket to the top deck. None of the original holes were re-used. It's in tight with all covers back in place. I hope sehunter is wrong about screws failing. Time will tell.
Tomorrow is a day of laying on my back wedged between the drivers seat and motor mount trying to find a loose connection to the 12V dash socket. Should be fun.
Best,
- bob