I thought the Big Time had a marked MB, negligible as it was. I've seen one and I thought it had a little BOMB mark. Maybe it's in the thumb and your driller drilled it out.
In any case, as you said, the MB diff is 0.001 and the general consensus is that under 0.010 (?) is barely worth mentioning and things don't really start to get interesting until 0.015 or so. As the others said, if you just have to use the MB to lay out the ball, draw 6 3/4" from the pin through the CG (weigh it after you plug it to confirm the CG location) and call that the MB.
SH