'68 Barracuda rear quarter window mounting washers

Getting the '68 Barracuda Fastback ready for the paint shop so yesterday I pulled the rear quarter windows and regulators. The rear quarter windows bolt directly to the window regulator using "snouted rubber washers" (my term - see pic.) to protect the hole in the glass and both sides of the window from direct contact with the steel bolt. My washers are shot after 44 years.

Where do you get new ones??? I haven't been able to find them yet - and I know I'm not using the correct name for them.

Thanks.