"As for the difference is overprint, I think that this is just an instance of the hot stamping equipment and/or chip picking up some foreign subtance that would prevent the hot stamp from sticking properly. Unless this is a "major" error emcompassing a larger section of the chip, properly not worth nothing."

The hot stamp is not just printed on the surface of the chip. There is an impression in the chip that the hot stamp occupies. No depression, no hot stamp. In this case there is no impression for the tail of the $.