Rear frame rails question

Thanks. I can’t find any with that kickout on it. All the ones I found are just the rail. Would you happen to know the panel they attach to? Sorry for the million questions, I’m just getting back into cars with my dad’s falling into my lap.
The "kick out"is just part of it, its where yhe leaf spring mount bolts to it. These cars are unibody so the frame rails spot weld to the body. These sections are spot welded to the trunk floor and to the rear panel where the bumper brackets mount.