They all have a ball joint at the top...least ways all the ones I’ve seen have. It was a safety device, the ball is fitted into a pre stressed socket so that in an accident if the mirror is hit by a person it will detach from the roof.
It is impossible to reattach the stalk to the socket off the car without the socket splitting in two, and it is extremely difficult to reattach the stalk with the socket screwed to the roof without damaging the paint on the stalk - a hammer is required!
If your stalk has become detached from the socket, I recommend sourcing a complete assembly.
Some mirrors have a shorter stalk than others, reducing the rear view, but rather than being late or early, I suspect these have been sourced from another model of car...happy to be corrected on that though...
I have a later car,& the mirror is stuck to the windscreen,& there are no holes in the roof lining,so I assumed there are 2 types.