I was all set to point out that it's actually "mother lode", but in light of the OP's posting history, you've probably got it right.
My freind.. It's an actual Counterstamp.. Not a big Mint Error.. Now most of us have told you what you have. Do you agree.. or still not yet? NH are the initials for the state of New Hampshire Here is one example I found Metal Detecting with a Playboy Bunny counterstamp They are usually in the same location. To the right of Lincoln's profile above the date.