Can you pop out a dent that has been repaired with bondo?

When my 67 GTS was in F5 tornado and completely covered the roof was mashed in and one body man said I would have to cut roof off. We took all interior back out and I laid inside on my back and gently pushed up with my feet and it popped right back in place with no need for filler. Of course it didn't have bondo in it so I can't say what would happen on yours, Joe