You can take a good magnet, wrap it in one layer of cotton (T-Shirt) cloth and slide it over bondo suspect areas of the car body.
If the magnet falls off easily, you know you are over bondo. If it sticks good and tight you are over good steel.
Suspect areas: lower quarters, lower rear of front fenders, over rear wheel openings. Lower rear window channel next to window trim, likes to rust there.
If it previously had a vinyl top on it, they were known to surface rust badly where the vinyl was glued on.
What does the inside of the trunk look like? That will be a good indication of what the rest of the body is like under the paint.
Taking the age of these cars and that it looks pretty nice right now, you can bet there is a good amount of body work under your existing paint job that is all going to have to be redone if you decide to strip it.
Considering you are just starting with bodywork, I would save that paint job, fix most of the bad cosmetic areas and put on a fresh coat of same color single stage paint.
Think you will be happy with the results for a driver.
Can always do a complete strip and repaint in the future, but that will be 4 times the work and expence.
Don't want to see that nice car in Auto Body Jail when you could be out driving and enjoying it.
A basic simple paint job, that does not have to be 100% perfect.
Your call . . go have some fun.
(12 years in the auto body/paint trade here)
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Saved this 20 year old Orange repaint on my '76 D100 driver. Fixed the areas that needed attention, spot painted with the original paint color to match, then hand rubbed the remainder of the finish with compound and distilled water.
Shined up nice and didn't have to do a complete repaint. Can take it out and knock around with it and don't have to worry about it. Works for me.
View attachment 1715723398
☆☆☆
