funola - I would say that is pretty accurate with regard to 1 & 2. At least that was my assumption. As for #3, I am not sure if that is dead center of the 1/2" hole. But probably pretty close. I just went through all the photos I took and this one below with the 13/64 drill bit inserted is probably the most "straight on" shot. So looking at that, I think you are quite accurate in saying that #3 is dead center.
Curious as to what you are getting at here? I think I have an idea, and now I am concerned.