Filed and sanded the flap mechanism assembly, then applied a coat of primer. Came up with a means of holding the back-rivet steel plate against the firewall (engine side) and was able to back rivet the flap backing plates from the inside of the cabin using the back-rivet set on the rivet gun. Sure like the results of back-riveting!!!
Primed and ready for installation
Using a 4x4 with a clamp reversed (light pressure) to hold back-rivet plate to firewall.
