68 B body quarter window bushings. Suppliers ?

On my 68 Coronet, I am needing the two bushings that mount on the rear quarter glass where the mounting bolts hold the glass to the inner assembly. I have the bolts but the bushings have disappeared. I have searched the internet & can't find any supplier who sells them. Hopefully there is a common source I have overlooked. Anyone know of a supplier ?

I wasn't sure whether to post in this forum or the restoration forum. Apologies if I chose the wrong one.

Layson's Restorations part# 351-41746, quarter glass bushing, 68-70 B-body and 67-74 A-body, $6.00 each

Thank you for the info !