I have some of the old stock certificates from the old GM. My wife's granddad gave her shares many years ago. I managed to convince her to sell most of them at $50-$60 back around 2003 when GM was doing well. She insisted on keeping some shares due to emotional reasons. They are worth more now as a collector item after GM was forced in bankruptcy.
Equity stockholders, preferred stockholders, many secured bondholders, and all unsecured bondholders were wiped out of billions of dollars by the quick government-forced bankruptcy. I doubt they'll be getting back in.