Welcome to the group Old Silver. In my short time here, I have found the group to be a great source of collective information, I'm sure you will too. One term that I read somewhere has become part of my vocabulary now, and when you mentioned the gravel-dings, it made me think of it. Since I picked up my '65 A/S last week, it came complete with "character marks", I'm sure earned over the years. Besides, bondo would not blend too well.
Again, welcome, and best to you.