If I'm understanding correctly, "X" holes are the same as Weight Block holes, and since none of the balls I used have them, would have been legal on that basis.
The rule about the finger needing to be over the hole is interesting. I can't imagine where else I would have put my finger, so of course it was over the hole. Maybe the rule is just worded that way because no one would put a weight block hole in that location, and the true intent is to limit the number of weight block holes?
Maybe it's just semantics, but I always thought (just on hearsay...not from actually reading the rules) that the number of holes a ball was alowed to have was regulated. Not hoe many of those holes were being used. In other words, it would be one thing if I had a ball drilled with no middle finger hole. But on the other hand... if I chose to deliver the ball by palming it, using none of the holes in the ball, would that be illegal?
Not that I would ever want to or be able to do that. Just seems that policing where a bowler places his fingers on or in the ball, would be very hard to enforce. Regulating the number of holes, however, is very cut and dry.
Just thinking out loud. Feel free to correct me if I'm looking at this all wrong.