The M is unique. I don't think it's old. The words, punctuation, printing and text is hardly ancient or clever.
Sounds like a 20 year old runaway.....and fairly recent.
Might even be just a ruse. I only say that because of what I did with my masonry tools in Virginia. :-)
Perhaps a “Clamper” prank?
The ECV society is known for such things (E Clampus Vitus Society)