2001 Bonneville Mirrors

My new-to-me Bonneville arrived with a single Mickey Mouse mirror (photo). I have been searching for a matching or close replacement for the right side, and I think this model year has unique mounts. The socket is stepped in size with 15mm I.D. at the top, 11.5mm I.D. and then 10mm I.D. at the base (visible in photo). The total depth of the socket is 23mm. Anyone have one lying around?

Thanks in advance.