Vinyl top cars came with bondo at the roof seams. Non vinyl cars came with lead. No matter what came out refill it first coat with Dura-glass. Its more flexible and water proof. Will not bubble.
Finish it off with a Light weight plastic filler. Always use Dura-Glass on any welded panel seams for the first coat. Remember to clean out the seam sealer in the gutters. Epoxy prime and re seam seal before paint