For what it's worth, I'm at 83K miles and have rebuilt mine twice. Mine does get wheeled hard. I would be willing to bet you are in need of a rebuild. Probably best to just do it - then you'll have a feel for how they should ride. I bet you notice a significant difference.
Make sure to replace your front bushings as well. I'd also recommend the flutter stacks and valve upgrades.
As mentioned, your other option is consider and upgrade, but those are FAR more expensive.
I managed to pick up a stock take off set a while ago. Having two sets has REALLY made the rebuild experience easier since my truck isn't out of commission while I get them rebuilt. I picked up the second set, in good condition, for about the cost of a rebuild, so WINNING!
Yup - that's why I replaced my rears already, but not the front. I managed to get a set of rears from a smashed truck that were rebuilt 10k ago for $250, so now I have a spare set. Still looking for a pair of fronts.