Some of them have longer reduced / threaded bits on the throttle side than on the clutch side, which is what makes them handed - DAHIK.
My G/S came with an almost new set of short mirrors, and of course I broke one within a few weeks. They were different from the short ones on my GS so I ordered a pair of Moto Bins short G/S items.
Just as well i ordered a pair , as they are different to the surviving G/S one, and the GS ones.
Apart from the arm length and shape. and covex mirrors , there is a difference between them all in the length of the reduced/threaded portion.
The longest are the later non handed GS ones so they could probably be cut down or packed out to fit most bikes but it might not be easy going the other way.