See attached picture.
I am going to be replacing the bushing that is pressed into the shackle.
I will be using an OEM rubber bushing, I do not want a hi-tech poly bushing, just want to replace what is there.
It appears they struck the shackle to create an indent so you can not remove/replace the bushing?? (both shackles have the same mark)

 

Sorry about the huge picture, try this

 

You can get a whole new shackle for $15-20, that's what most of us do.

 

Agree - you can't avoid the possibly difficult part (removal of the frame to shackle bolt) either way and depending on how much a PITA it is to get the old shackle out - you will probably be relieved to NOT have to press out the old bushing and press a new one in.

I used the Crown OEM style shackle when I did my leaf springs recently and feel very happy with the price (about $20 on Amazon), fit and quality of the part. I've had zero issue with them functionally, though I've only had them for a few thousand miles so long term durability remains to be seen.