Rear window regulator - W126

[420 SE]

G'day

The rear R window on my 1988 W126 420 SE is broken. The little plastic/nylon guide which hinges between the relulator arm and the channel along the bottom of the window has disintegrated.

In the Fastlane shop section I noticed a part which looked like this bit (although it appears I can't buy from this site as they don't ship outside the US). Picture from the FastLane catalog.

Now assuming I can get one of these parts over here (AUS), how do you go about replacing it? It doesn't appear that you can get the pin/post (whatever its called) off the end of the regulator arm.

Or is it just easier to replace the whole regulator with a new/2nd hand one?

I think the L rear is about to go soon as its making the same sorts of noises as the R one did before it went and I guess if I'm going to change them I should probably do them all.

Cheers