Confused on Spring kit 68 dart

I bought a drum "hardware kit" at Autozone a few years ago for my 65 Dart w/ 10" drums. Cost ~$9 and each kit does both sides. It has the later self-adjuster, which works better than yours. Just ask for a ~1973 Dart. My only issue was that my rear shoes are thinner, so had to re-use my "shoe pins". You can find photos here or in the shop manual of how it should look assembled. I don't even think it is even "Mopar", just the basic "Bendix" design used on most cars. I use gasoline and a brush to get my backing plate spot-less before adding components.

I would definitely change the rubber boot on your upper ball joint, and the joint itself if loose or rusted. A few blows w/ a pickle fork should separate it, not like you need to worry about ruining your boot. I always use polyurethane boots.