My guess, and it's only that - a guess, is 2nd week in October. That's if it's marked clockwise as we're looking at it. If the person marking the die/mold was going clockwise, then it's reversed on the part which would then appear to be 1st week in July.
There's 12 divisions, and no more than four marks in any of them (granted a very small sample size). Sure points toward a month/week system, but I may have misinterpreted whether the "ticks" or the "spaces" represent the months. Does "0" = January, or is the first space = January?