Um.... no difference in any of the 6 pairs I have had other than L or R Base.
Your Drivers side is a body but I don't know what your Passenger side one is from.
May be a 1970 E Body one? They had simular small bases.
No, the 1970 ONLY E-body ralley mirror have completely different bases made for the angularity of the door.
The A-body rallies are the same as the rarely optioned 1970 B-body rally mirror.
The drivers and passenger mirror tops will not interchange for any Mopar remote mirrors, chrome oval or rallye type.
It's just the top mirror housing is more pointed on the passenger side.
I just went out and measured.... the passenger mirror itself is wider and shorter thant he drivers side. So yes, the actual mirrors are different left to right.
I'm thinking of sticking them on my 68 Barracuda in hopes to actually see out of the passenger mirror. I'm hoping the mirror edge is out more so I can use it. I haven't tried it to actually find out.
My O.E. 1968 passenger mirror (remote style) that came of the assembly line is totally useless. All the other 68 (I sure others too) A-bodies seem same thing. Maybe different due to seating position or how tall you are, but I doubt it.