The small tapered piece is your caster adjustment. Interesting you only had one of these (on one side) but this is by far and away not the only time I've run across this. People seem to lose these, remove them or something. Your solid front axle doesn't bend so if somebody was trying to reduce caster on one side (maybe to compensate for road crown), they failed. When you get new springs (and the ones offered by Dorman are made in the USA but as I predicted you now have several opinions on who and where to get them) just be certain to get new caster adjustment shims. Your caster angle should be 1 3/4 degree +/- 1/2 degree. Usually I try for the top end or 2.25 degrees. More caster means you'll drive straighter and your wheels will re-center themselves after a curve or turn. If you exceed 2.5 degrees your truck will become more difficult to steer. Less caster means your truck will be easier to steer...and at a point too little caster will make your truck wander around like a drunk billy goat and become very unsafe. Good luck!
