I believe when you order them from Paul Conway they are sent curled but I am not 100% sure if they still are sent that way. I bought my first one over 9 years ago so they might have changed but you can always call and ask them.
They send them flat, but you can buy a metal strip for a dollar extra and you can curl it as much as you want. My brother and I bought ours about two years ago and I ordered three more for guys at the station about six months ago and all with the metal strip, you can stop by station 9 if you want to check them out. This one fits on my n5a and my ben 2 plus