It is normal to see some of the surround of the cone covering a portion of the mounting holes. The outer dimension of the cone must be larger than the inner dimension of the front sealing gasket. This ensures the surround of the cone has enough surface area for proper placement and adhesion to the frame. It is safe to punch your mounting bolt or screw through the material covering the mounting hole. Just be sure you do not harm the cone inside the inner dimension of the front sealing gasket.