Until 1992, all of the SF proof sets, with the exception of special sets, were clad. Starting in 1992, the Mint started producing the Silver proof sets. Each year since 1992, they have produced both a clad, and silver proof set.
Yes, the late 70's, with the exception of 76, would be clad.
Yes, the late 70's, with the exception of 76, would be clad.


















