With the price of copper, you'd want to chemically strip it so that it can be reclaimed.
Shot peening wouldn't be a good way to remove the plating. Doubtful if peening would do much except make it look pretty.
Depends on the machine and it's setup. I had a couple 10'x10'x14' shot peen blasters for stainless and aluminum parts at an old job. They're effective. I wouldn't doubt that the copper would be long-gone, but unless care was taken to protect the big and little ends, you wouldn't have much left to grind/hone/finish after re-machining the bores.
Copper prices have also fluctuated over the years. Some years it's definitely worth reclaiming, others not so much. Most shops I knew that dealt with it would sit on scrap until the spot came back into favor for recycling. Chemical stripping also isn't cheap these days with EPA water discharge regs and the like for manufacturers - so I could see blasting it off if the price was way down.