From my '65 Valiant Signet Convertible. First foto passenger mirror mounting holes, Second foto driver mirror. My tape measure is a little off from the hole in the first foto, but nonetheless the mounting seems about the same distance from the chrome pillar moulding (which only convertibles have).
The passenger door holes on your car line up with where I test fit mine. Apparently my driver mirror was added as a single, perhaps by an owner. Many pics in the gallery don't show any side view mirror.
As I'm going to paint the car in the future, I'll move the driver side back to match.
Thanks for the photo help.