Although it is not possible to provide you with specific advice without direct examination, some generalizations may be helpful to you. Generally speaking, insurance companies do not provide coverage for breast augmentation or lifting ( both of which may be helpful after significant weight loss after gastric bypass surgery) or tummy tuck surgery. Panniculectomy however may be covered depending on the health insurance plan.
It would be in your best interests to seek consultation with well experienced board-certified plastic surgeons who can demonstrate significant experience helping patients who have had significant weight loss.
Web reference: http://www.poustiplasticsurgery.com/weightloss.htm