My Dad’s neighbor, in Syracuse, a few years older than Dad, enlisted, after Pearl. The story I was told; as a B-17 Top Gunner (position behind the cockpit), during one mission, he bent down to pick up his dropped cigarette. While he was bent over, the plexiglass dome was blown to bits. One of those cases where smoking doesn’t kill ;)
I'd be willing to bet that he kept a piece of that broken plexiglas for good luck!