I am a bit amazed that there aren't any photos or illustrations of the remote mirror in any of the service manuals or my 1965 parts manual. Here are some photos of mine, sorry about the poor quality. There was not a passenger side remote control mirror made for our 1965 GSs. However, they did make a manual mirror for both driver's and passenger's side. These are now being reproduced and most of the major after market suppliers have them. They should have they Buick trishield emblem impression on the back side of the mirror. I have seen the correct remote mirror for sale of Ebay, but nothing there at this time. Here is a contact who advertises in the Buick Club of America's monthly publication as parting out 1964 through 1967 Buicks. He should be able to help you find the correct mirror. Mark Polastry in Elgin, Texas 512-303-0833. Good luck.
John