I haven't replaced all my genuine Canon caps, but whenever I buy a used lens with no cap then I buy one of these to go on it, never had a problem. They look basically the same, just no Canon logo (i don't see the point, it's just a cap). They come with a hole in the side and a thread to use on it, no metal loops someone else said, but I don't bother with the threads, I've got them all in a box somewhere...
(although I have had a problem with a $2 chinese non-centre-pinch 86mm cap, it got borked in post. Didn't bother complaining, I just bought a $3 one instead and it's worked fine since).