61 Valiant- Windshield wiper spline bushings

Those were never Chrysler parts. They came with aftermarket universal replacement wiper arms such as the Anco 41-03, to convert the pre-'65 wiper arm attachment point (cone spline with a central bolt) to the '65-up attachment point (drum spline with angled spring retention).

The 41-03 was a great product, but it was discontinued some years ago. Plenty of Google hits, but all of them are dead ends. :-(