Are they a name brand the ones you bought at dunnams? Normaly if they are non corrosive it will say on the box. But more than likley they are corrosive. Those listed in the spam can are mil surp and are corrosive, no big deal just clean out the bore with some water after he is done shooting
The bullets I bought at Dunhams were just wrapped in paper with a little twine. There are no stamp marks on the bullets. They are plain but shiny.