Front leaf shackle bushing?

[cysko9]

I'm in the process of putting a 4" lift in my 73 blazer and found that the link connecting the rear of the front leaf to the frame has a bushing that is beyond shot... I think that part is the shackle but I'm kinda new to 4wd and suspension work so I'm looking for some input on if that's correct or not. It's the bushing that actually goes through the frame... I've got all the restt of the new bushings in the lift kit...

Secondly, where a good place to get a replacement. I looked on rock auto but wasn't sure if I was looking at the right part.