As per the title - is this rubber rand something that is part of the windscreen or something that is put on after the windscreen is in place?

My Mkll does not have any rubber around the windscreen, just a butyl seal under it.

That's what I am on about. Is it part of the windscreen or something that is put on it after the windscreen is fitted.

It's a polymer, comes out liquid from a squirt gun and cures to a rubbery texture.

Its actually applied to the car or new screen before fitting and 'sticks' the screen to the car

Its not the glue or silicon sealant I am thinking about. Around the top and sides of the windscreen is a 1cm or diameter strip of rubber. It serves no purpose interms of sealing/sticking etc but seems to be a way of tiding up the screen/A pillar interface.

I don't remember that, but surely it's just trim. The windshield is only glued in with the above rubber.

No idea what you mean. I've never seen anything fitting that description on an Octavia.