1968 through 1998 PROOF sets – Lot of 31 Sets! Lot of 31 Sets. Get all the Clad Proof Sets from 1968 through 1998 at one time. All sets come with original government packaging as pictured. Boxes will be in above average condition. Many sets are brand new taken from mint mailing boxes. All Proof and Mint Sets Available at. Visit Timer’s Coins. Track Page Views With. Auctiva’s FREE Counter.