That looks like the correct part. The rubber on mine has perished and crumbled away, though it still works. If you look at the photo of the part close up, it looks like it snaps in from the outside and it retained by the clip as each end. If you can try and prise it out at one end whilst pushing it towards the other side it may pop out. I've removed the rear trim on an FD hatchback by removing every screw I could find, then tugged on the trim until it snapped out of place. I think I did crack it though. It would only help with the tailgate switch if you could push back the end clips from the inside.
I would try prising it out first before removing the trim.