Hi gang, I have a 2009 2500HD GMC Sierra and need some help removing the grille. Last time I did it, I was able to get it partially out, but the bumper cover/fascia trim panel that wraps the top of the bumper is attached and I couldn't see how to release it. I need to remove the grille to drill a couple holes and install rivnuts on the diagonal radiator cross brace on the passenger side to install a Whelen SA315P Siren Speaker and the SAK24 mount. In order to do this, it will require full grille removal to accomplish this task. Attached is a pic of where the holes need to be drilled and the rivnuts installed. Pics or detailed instructions from the service manual would be appreciated. Thank you in advance!