5th wheel pin box

Simple as it looks... but heavy. It might be hard to get/reach the nuts inside the box but other than that, piece of cake.

I would think there should be at least 4 bolts on each side.

Even the original pin box has only 6 holes but it looks like only
4 are used.
I was wondering if there are any tricks to removing and replacing the box?
Seems straight forward to me, but that is what concerns me

My pin box has 12 bolts that hold it onto the trailer. I have a hard time believing that there would only be 4 bolts holding yours on. When you are towing the trailer, the entire weight of the trailer is being pulled by those bolts attached to the pin box.

I don't know how many bolts there are, but those boxes are heavy. Have at least two people when you do it.