Great find tmg513.. well done. Also in that image the silver "C" clip can be clearly identified as holding pressure in the assembly.

Doug, from a VERY dull memory,as you suggest the threads on the plastic "nut" are all to simple to cross thread and I suspect many will be, when I fitted the gearstick on Fords of the time, it seemed best to remove the C clip to take the pressure off the rubber spring and provide more of a feel relative to getting the threads to match the housing.
My pal ran a Cortina with the whole assembly loose, so it is possible to run that way. His car was stolen as many Cortinas were, but whoever stole it could not master the gear change and abandoned it a few streets away..(-: