Original sealed 1956 United States Mint Proof Set Tennessee Valley Hoard. Original sealed 1958 United States Mint Proof Set Tennessee Valley Hoard. Once in a lifetime collection We are proud to bring to auction the greatest proof collection of the late 1950s and early 1960s. Finding cameo and deep cameo proofs from this era is near impossible u less you pay full retail and buy them already holdered. All of the sets at coin shows have been examined and have virtually no cameos. The only way to get the same odds of finding one of these valuable cameos is to buy an unopened set.