Side view mirror question

[Stvbrtls]

I am beginning work on a 69 C/10 CST LWB that my late father in law gave me. I am relatively new to the forum and have gotten some great information from its users.
My first project for the truck is to find a replacement mirror for the pass side door. It currently has a painted mid sized tripod mirror (Option code D29 R/V Mirror-Jr- L & R) on the driver's side and I am trying to find a match for the pass side. I have looked through the for sale items on the forum but have had no luck.
I just need some ideas where to look for one.

I will post pictures of the truck when I figure out how to do it.

Thanks for any help.