Displaced fractures or fractures involving all supports of the cheek bone (trimalar complex, Temporozygomaticomaxillary fractures) need to be fixed close to the time of the injury with plates and screws. Failure to do so allows the chewing muscle to pull the bone down resulting in facial asymmetry and an elongated orbit. Correcting this fracture after it healed poorly is very challenging. No one knows what each insurance would do. It is clear that a lot would depend on your policy and how it is interpreted by the person reading your surgeon's request for permission to operate. Personally, if you do not have a documented functional disability it is unlikely that they would approve such surgery since it would be regarded as cosmetic in nature.