At the last convention, many dealers were offering the generic 7s and 28s for face (and some even below face) with almost no takers. One told me he was buying the sevens at $3-3.50 just for the silver value. I would be very hesitant to load up on these.
Caveat: there is a "mule" with Colorado generic on one side and Deadwood Saloon Number 10 on the other. That's a worthwhile strike for sale or trade.