I would guess it's a minor die break or crack. I'm no expert with this series or with errors, but that's my two cents.
Looks like a die chip, so yes it is an error. I just don't think it would command any additional premium. Keep up the hunt!
Prob not non cents, not really anything special I guess. Just never know though, I've seen some wheat errors that leave u scratching ur head that do! :scratch: