That looks like an early style spring mount (arrow) like what were used on the narrow (pre 76) 1.75" wide springs. Not really a big deal if you're swapping out the outers and just using it to get by. Looks like someone had a ball putting that CJ puzzle together.
And no I'm not buying a CAD program to make a demo diagram here, live with my crappy 'paint' job
The body underside looks good, get at the bad spots, rhino line it and that tub will last you many years yet. Or if you ask jeepjk4dr he'd say it's got 30 years left on it the way it is
I still have some Bendix disc stuff and other intermediate year hubs, axle shafts, crap that hasn't been scrapped out yet. Lemme know if you need any parts during the swap. I may have them and I definitely want to get rid of all of them from the barn.
.....that reminds me, jeepfreak81 owes me his first born for a 10 spline bull gear that came out of the hay mow