Well, we don't know what the original poster had in mind? If he or she wanted to, say, replace the shaft, and knew something about the new one (weight and location of its center of mass), but didn't have it on hand, he/she could calculate the change in balance point for the new combination. The same could be done for a new weight bolt if the old one was extracted and its characteristics thereby known (weight and position).But,,,,you don't know the size and type of the weight bolt nor the pin.
I'm not a cue maker, and if you are, obviously you could offer more pointed advice than I can. I was just speaking in general terms, since we don't know the purpose or circumstances of the question...at least I didn't. All kinds of odd situations come up.

Jim