Repairing a Bondo repair

I would say if it’s cracking it may be worse than it looks. looks like it’s on the joint where the quarter meets the roof. These were originally leaded in. If it were mine and putting a vinyl top on, I would sand the Bondo away until I found clean metal. Clean and neutralize any rust, seal it and use All Metal (similar time Bondo but aluminum based). I just repaired those areas on my super bee.