I don't think this is a DDO, although I'd love for it to be. It came out of a 1969 UNC mint set. Just wanted to confirm my thoughts.
Mechanical Doubling. A big clue that is MD is that the doubling shows the on the date AND mint mark. The date comes from the master hub but the date comes from a punch on the working die.
check coppercoins.com http://www.coppercoins.com/lincoln/diestate.php?date=1968&die_id=1968s1do007p&die_state=eds