I noticed that the V puncture is almost perfectly aligned to the contour of the O. It could have been a factory accident, but the mark's seemingly punctilious positioning just coincides too much to human mannerisms to have been accidental, atleast IMO. Also considering the observation that it appears to have been very precisely executed (clear V shape) and carried out with a sharp object, I would have to believe it was intentional.
Maybe the V is a clue?
Maybe the V is a clue?