I've been through 3 boxes in the Detroit area and haven't found anything older than a 1971. I also believe some money companies (Brinks, etc.) pull out silver coins when they roll their coins so this could be a reason.
With that in mind, I did find this last night, a 1972-D with no FG, so that made up for not finding any silver out of that box :)

With that in mind, I did find this last night, a 1972-D with no FG, so that made up for not finding any silver out of that box :)



















