Rotating assy balance

I don't have a pic of the piston rod assy. The rod end has been heated to get the wrist pin in. I don't think I can easily press them out, but, naive.
The big end has been machined so probably align bored. Looking at the numbers more, maybe he is trying to get each journal weight close. Still, his sharpie only tells me where 4 of the caps go. Not a happy camper.
Why would you need to remove the pistons at this point?