MS is the state of the coin (uncirculated as opposed to proof) PL stands for Proof Like where it has almost a mirror look to the fields, DPL is Deep Mirror Proof Like where the mirrors have at least 8 inch mirrors which means you can hold the coin at least 8 inches from normal font on a business card and read it from looking at the coin. A DMPL coin looks like a proof coin looks in the field
The Redfield hoard was the coins of LaVere Redfield. at the time of his death in 1974 his estate was worth about 100 million dollars. In his home he had a fake wall built and inside that fake wall they found 411,000 silver dollars he had hoarded which is about 11 tons of silver dollars. at one time LaVere Redfield had amassed over 600,000 silver dollars. In 1963, his house was burglarized, and it was reported that approximately 100,000 of the silver dollars were stolen. That is probably what encouraged him to build a false wall in front of his coal bin. the Redfield Hoard is coins from this collection of Silver Dollars. Steve Markoff purchased the hoard from the IRS for 7.3 Million Dollars when the actual value was about 20 million. Paramount International Coin Corporation in Ohio was one of the companies he used to liquidate the hoard in a 3 year plan so not to flood the market with all the coins and they packaged them in the hard cases which looks close to the GSA cases but have the red label instead of black and either say "A Silver Dollar from the Redfield Collection," or "US Silver Dollar, Paramount International Coin Corp."