What you could have is a repunched mint mark. Its a little different than a true doubled die or machine doubling...if that is what you were alluding to. I have several RPMs from 1964 on many of my coins. It seems like that was a big year for that. But my scope is limited and you may want to wait for the real experts to join in. Because I am still learning this like many of us are on CT, it doesn't look like much of anything, but if I were to bet, I would say RPM. Keep on looking, your doing a great job and your enthusiasm is contagious.
I think Rock may have found the right die http://www.coppercoins.com/lincoln/diestate.php?date=1964&die_id=1964d1mm002&die_state=mds or this one http://www.coppercoins.com/lincoln/diestate.php?date=1964&die_id=1964d1mm001&die_state=lds
But if I am wrong I will say I was wrong Joe I think Rock in the same boat as me I need to go look it back up and make sure what I am advising. We all know no one right 100% of the time.
You've got to be kidding. If you can memorize the 1960 mint marks you would be quite the man. This coin has a few as well to put to memory.
It is the 1964D-1MM-002 I checked out the "T" in "LIBERTY", and it has that die crack on the "T" Thanks guys! I appreciate it:hail:
