Brakes for your truck are the same for GM trucks up into the early '70's. But unless the springs drop out or don't take much effort to remove, they're probably OK. I don't see an issue from the pics you posted.
If you really need them, put a post in the parts wanted forum here, and maybe a fellow Bolter has some to spare that he'd be willing to mail to you.
[on edit] AC Delco 18K1597 hardware kit from RockAuto should fit your truck. The adjuster springs look a little different, but should work fine. Not bad pricing at a little over $6 for both rear brakes.
Last edited by klhansen; 03/12/2021 7:30 PM.