To the best of my knowledge, there was NOT a passenger remote option for 71-73. Never seen one, probably never will. There was however, an option on a Granada I saw in a boneyard for this exact thing. I was going to swipe it, but never got the chance. The remote mounted in the dasboard, nest to the radio. Most likely, someone swapped the guts of the granada mirror into a mustang housing, or it's just a granada sport mirror that was installed on a '72 Mach1 as the ad states. Just because it was bolted to a Mustang, doesn't mean it's a Mustang part.......