I bought a 1957-D mint set card last year (there was no P card) at a Very reasonable price. The dealer just wanted to flush the card from his inventory as it was only half a set. Here are the Franklins from the card. The images are by Bob Campbell, and I think he did an excellent job.
Inside the 1947 - 1958 Mint Sets were 2 or 3 cardboard cards, one card each for each Mint, PDS, that minted coins that year. Each Mint Set card contained two examples of each coin minted at the given Mint that year. One coin would be displayed obverse up, and one coin would be displayed reverse up.