The pillow blocks are straight aluminum, no inserts. And while the car may be 40+ years old it had less than 5 years of use. It is possible that there was a smear of grease on the sway bar, but generally dis-similar metals will not gall the way like metals do.
Thanks Chad for the links to the L9 hardware. They could well have been a later addition, they weren't even drilled for the safety wire.