In 1967 the US Mint did not produce any uncirculated mint sets because of poor sales the previous years. Because of demand the mint produce these coins that were struck with polished dies to produce a proof like finish on the coin and were considered the best coins from this process and had the most proof like surfaces of the 3 years. Some even were found to have cameo like devices that made them command a higher premium and why the 1967 dated coins command a higher price than the previous two years. Coin will come in a paper, vinyl, or mylar, or a 100% archival quality plastic coin edge holder.