How about this:
https://www.schaffpiano.com/Upright-Damper-Rod-Hinge-3-8-Wide.
It may not be exact OEM, but looks like it might work, even if you had to file the hole a little.
You'll have to register with Schaff if you haven't already. I'm not sure that the link above will work without logging into the Schaff website.
Good luck.
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Paul McCloud, RPT
Accutone Piano Service
www.AccutonePianoService.compavadasa@gmail.com------------------------------