Dino 308 GT4 make of external Mirrors?

I have a '74 series 1 GT4 that has Californian mirrors fitted, but the driver's side is different to the passenger side and the driver's side is broken so I'd like to replace it.
On the driver's side the fatter/wider portion of the base plate is towards the front rear of the car, which is the same as the new ones that are available. Whereas the passenger side has the fatter/wider portion towards the front.
I suspect the passenger side is original because it better matches the rubber pad that it sits on, whereas the driver's side doesn't.
Can anyone shed any light on this?

Thanks,
Paul

 

I don't have my car handy to check but its mirrors also differ left to right. As I remember the attachment isn't the same.

 

Hi, David.

See PM and email, please.

Jack

 

Thats what mine had

 

If you are starting from scratch, you may want set them differently front to rear so the window frame doesn't end up in the middle of the mirror.