Dan, you may be thinking of the typical shackle that has bushings in the spring eye and the frame mount with pins and bars on each side.
But 3/4 ton trucks apparently have a different type of shackle, a male and female setup if you will.
Here is a link that has a picture.
Maybe the PO can give the Filling Station a call and see if they have the proper bushing (the one that goes in the frame or the one in the spring eye)
