Not sure if there is a difference between pre and post facelift but I know that non oem seem to have a bit of plastic that stops the bumper clipping in properly and you have to remove it from the clip or cut a notch into the bumper to make it fit,
I recently fitted an 03 wing to my 04 car and the clip that came with the wing was different to the clips that were on my car I had to alter it to make it fit.
If you can check your old bumper to see if it's been modified to fit the clips you have.