The 1928 is the third Oregon Trail issue and was part of the weird situation for the the first three Oregon Trail commemorative issues.There were 47,955 1926 Philadelphia Oregons issued. Then there were 100,055 1926 San Francisco Mint Oregon minted, but they didn't sell as well and some remained undistributed until 1933. In 1928, the Philadelphia Mint struck 50,028 Oregons but declined to release them until the 1926-S Oregons had been sold. In 1933, the 17,000 unsold 1926-S Oregons were melted, allowing the Mint to sell the 1928 Oregons that had been sitting in their vaults for 5 years. Wayte Raymond of Scott Stamp & Coin in New York City agreed to market the 1928 Oregons, but requested that all but 6,000 be melted and the Mint acquiesced.
It's a weird and sordid tale, but all of that aside, Oregon Trail commemoratives are very beautiful and today they are quite popular with commemorative collectors. The 1928 has a modest distributed mintage (though originally manipulated by melting) of only 6,000 coins. It is kind of scarce today. In terms of overall survivors, the 1928 Oregon is 5th rarest of the 14 Oregons, after the three very low mintage 1939 isues and the 1936-S. In Superb Gem condition it is one of the tougher Oregons, but it's a relative concept as most Oregons come very, very nice. The typical 1928 is well struck and has nice frosty luster.