What have I got here?

[MidLifer]

I have been at this hobby for 3 years and I still have so much to learn. See the attached picture. My 1971 C10 originally came with option G50 "Heavy Rear Spring" according to the SPID. At some point the PO changed the truck over to 8-lug wheels and installed a 14-bolt corp rear from an early 80s truck. It has a leaf rear. It also has some kind of helper springs attached to the frame rails (see picture) and it looks like he welded some boxes onto the axle to support them.

My question is - is that a GM thing or did he do some form of aftermarket beefing-up of the rear suspension?

What might happen if I were to remove those? I am trying to mount a receiver hitch on the truck and their presence is limiting my choices.

The guy died before I ever met him so I can't ask him. Hence I'm coming to you guys and your deep well of wisdom.