1956 1957 1958 1959 1960 1961 1962 1963 1964 Proof Set Silver Flat Pack U. Dime quarter and half dollar are Silver Proof. All Franclin Silver Proof Half are getting rare. Only Kennedy Silver Proof 90% Silver coin in 1964 Proof Sets.
Hard to find silver Flat pack. Most were Melted in 1980's.