its a steel material. I have holes in mine where a spoiler used to be attached but its been sealed with paint.
you may find removing the spoiler that the screws & holes are only part of the issue.
My spoiler was a Rod Millen spoiler but it was also attached with some serious double sided sticky tape. I have some pics somewhere but I removed paint while removeing parts of the tape.
In my case it didn't really matter as I was repainting the whole car anyway. I'm sure with a bit of patience you can remove it without damaging your paintwork.


