I had to take the glove box out of my b7 because the hinge snapped, so I took my damper off whilst it was all out. You should be able to remove the damper with the glove box in situ, but if not its only 5 bolts holding the glove box in (3 inside at the top and 2 underneath). Only takes 5 mins to get out and you'll need an 8mm socket.
I used wd40 inside my damper and shaved the o ring. If you go down this route, Don't put too much wd40 inside it or it will make a weird noise when the rod moves. The noise went away after a bit though
I'll try and have a look in the garage tomorrow if I can find what my dad used to replace the pin and let you know the sizes.