Just a quick update. I am 1/2 done stripping the primer back down to bare metal.
Found lots of small areas that as primer was being sanded off and almost gone but with still a thin layer left, they looked soft. These were mostly areas that did not have any filler on them, just primer. I could easily scrape the primer off leaving bare metal below. I could also clearly see as the primer was removed that there is a black film on the metal. If I sanded the bare metal a bit more I could get through the black film and the metal below was shiny. Using my finger, I can feel that the darker areas are very smooth compared to the shiny sanded areas, even though the panels were originally DA'd with 80 grit.
100% without a doubt, this would have been a catastrophe sometime later.
Still have tons of work to do to get these panels cleaned up and ready for primer again, but definitely glad I chose to start over.
Thanks
Michael