2007 -p John Adams error dollar

I found 2 of these in a Wal-Mart postage stamp machine a few years back and it was given back as change, I had one graded and just kept the other in a holder. You can't see it in the picture but the edge of these coins it was stamped with the date, the "in God we trust" and the "E pluribus Unum" these coins somehow were stamped twice but upside down from each other so the edge lettering can be read on the edge both right side up and up side down at the same time.