The driver's side of the car in the rear quarter had suffered some sort of impact, hard to say if it was a tree, another car hitting this one, maybe this car sliding sideways into something... hard to say what happened 30-35 years ago but the dents on the top of that quarter are old hammer dents.
Metal bumping is truly a bit more of an art than simply pounding out dents. You need a good hammer and dolly set and you have to be sure you support the opposite side of the metal with the dolly with care to NOT strike directly on the dolly.
This is the most common mistake with hammers and dollies. People see the hammer and see the dolly and assume that you line them up directly and bang away to straighten out a panel.
You never want to hear that "ping" noise when striking with the body hammer. If it pings then you are hitting directly on the dolly and you are flattening the sheetmetal between the tools. this results in stretching, which is bad.
You always want to support a low spot with the dolly behind the panel and strike a high spot with the hammer on the outside, this raises the low spot with hand pressure on the dolly and the hammer sinks the high spot.
If you "ping" then you are stretching metal, if you stretch it then it doesn't fit within the area any longer so you will have an area that needs to bulge either in or out.
It gets a little more complicated than that with the selection of hammers and dolly types used but that is the number one rule, never "ping".
