Owner Comments:
Mexico 1768/7 1/2 Real graded by NGC as AU Details "cleaned". I considered the "cleaning" light and thought it might straight grade. I guess not.
Gilboy M-05-45a, KM 68 type; overdate unlisted.
Quite rare as an overdate. According to Brad Yonaka's book "A Variety Guide To The Fractional Pillar Coinage of Mexico City 1732-1771" eight examples known. So this would be an additional example.
This coin sat in my collection for at least a decade or more before I took it out to look at it and noticed the overdate.
Initially I thought it might be an 1768/6 or 1768/6/7 (double overdate). According to the book, the 1768/6 is noted by Gilboy (M-05--45b). This may refer to the reverse die shown (in book), which has a distorted on left side of the 8 but no other markers suggesting a 6 in the date. As such it is not conclusive.
This appears to be the only example graded at NGC
PCGS has one graded at VF35 and the overdate is not easily recognized in their photo.