The ole grey bottom sounds like it was having a great time doing what it was built for, turning dirt. I have a 2N that I haven't even started in a couple of years because I haven't done a garden.
I think those go on each side of the plant to keep dirt from being thrown on young plants for the first cultivation. There are four because that was a two row cultivator setup. Half plows/buzzard wing plows and disc hillers are used for pulling up beds.