Missing bushing on the rear end?

but to make matter worse, i got to the other side and notice....

And yes I realize that the shocks/spring/LCAs are ****, I'm working on that, but what's the P/N to the bushing and how much is it for the pair?
you might as well replace both, i had one go bad so i only replaced the bad one, and 3 months later i found that my other one was bad
not worth the time and hassle of getting all of the tools back out, jacking the car up, etc. when you can just do it all at one time
it takes literally 5 min to replace one side if you are working slow

