I just did some work on my MorRyde pin box last week as I had to move it from the bottom position to the top position on the frame. I did that because the 5ver was nose-high when attached to my stock 3500. DO NOT attempt to do this alone without some type of lifting device. I strapped the pin box firmly to the top of my cherry-picker type engine hoist as I had to remove all of the bolts. You will not have to remove all of the bolts because you do not need to change the position of the pin box.
You really wouldn't need to move the pin box back to its original position, but if you would like to move it back to where it was, it is fairly easy to move if you loosen all the bolts and use a little leverage to move it. You may have to be a little creative here, as to where and how it needs to be moved, but my pin box didn't seem to be binding much between the frame mount plates and was easy to move. You will be able to tell where it was by the paint lines on the inside of the vertical frame plates. You will need a flashlight to see if it had moved at all.
It really helps to have a 15/16" box end wrench with quite a bit of offset as you will need to get around the protruding bolts, unless you remove the back two bolts to torque the front one, then install and torque the middle one and finish up with the back one. Then you can do the same to the other side. (If you were working on a heavy casting, I would not suggest this progressive method of assembly. But, since these plates aren't very heavy and will flex, it shouldn't make much difference on the final torque values.) If your pin box is in the top position, there is absolutely no extra room to have any swing with your wrench that is on the nuts inside the pin box.
The torque table I used is posted by boltdepot.com and lists the 5/8" course thread, grade 5 bolt to be torqued to 112 lb-ft. The indicators on your bolt heads show that you have grade 5 bolts.
One last suggestion. Raise the front of the 5ver so you can work under there standing straight up. I wouldn't have been able to do my work if I had to stoop over under there. I am just too dang old and worn out.
With the right tools it is an easy job. I am sure you can do it. Good luck with your venture.