Those are aftermarket bushings for an optional (rear) or original (front) sway bar.
Me? I ordered first the Raybestos "OEM fit" for my 1988, but they were for a smaller swaybar, so I then measured the bar and ordered some poly ones from Energy Suspension that are greaseable (to help keep the "OOkookOOKook" down)
They actually spread EASIER than the rubber ones did, go figure.
Still, they're not exactly "Jump on up in here!" easy.
Good news is, with my bar out, I can slip them on a lot easier.