['ol Pinion head]

Dont believe I've ever read of original 2nd Gen WS6 bushings being referred to as of POLY construction.
Instead have read several times that the WS6 rear sway bar lower bushings were made of a harder durometer rubber. Do know these black swaybar bushings were identified by a different color of stripe on the flat section of the bushing. Have several pair that I put up decades ago, the least usage sets I picked up off the ground under two '80 Indy Pacecars that were being parted at huge local late model GM yard, that was in 1982.

The front swaybar link bushings went from being made of rubber in normal applications, to with the WS6 option, being made a of an off whitish color hard material that yellowed some with age. Those front link bushings had no give to them, more resembled the construction of a faucet seat washer. in late 83, maybe early '84, Herb Adams VSE had a sale on swaybars , & I removed my original front bar & rear WS6 bar & after swapping on the Herb pieces, kept all the original bushings.