I would bet money that they are factory use sockets. I would also bet money that they are proto or apex. A tool store I go to gets production used sockets and other stuff really cheap. They have a lot of new Blackhawk/challenger as well. They get sockets by the crate, and there is usually a good mix of proto factory used(not marked) and random unused other brands like snap on, lisle, cornwell, mac, lots of sk, etc. I wish I knew where they get these crates from. You could probably build some nice sets.