Insurance Coverage for Septoplasty

Health insurance should cover both Septoplasty and rhinoplasty in your case, as the deformity was caused by trauma.  Having said that, unfortunately many insurance companies try to get out of paying legitimate claims, and having a surgeon that would also be a good advocate on your behalf  with the insurance company would help.

Typically a skilled surgeon should be able to properly execute both rhinoplasty and Septoplasty at the same time.  Make sure you interview 2-3 surgeons, find out about their experience with your type of deformity and expected outcome both functionally and aesthetically.

A good rhinoplasty surgeon, whether they are an ENT or Plastic Surgeon, will be more than capable enough to do both a septoplasty and a cosmetic rhinoplasty.
However, insurance will only pay for the septoplasty portion of the operation.

Septoplasty is a surgery performed to correct a deviated (or crooked) septum. The septum is the piece of cartilage that separates one side of the nose from the other. Normally, the septum is straight. When it is crooked, it is termed a deviated septum. A deviated septum can block the nasal passage and contribute to symptoms of nasal obstruction.
A septoplasty does not change the shape of the nose and is therefore considered a functional procedure as opposed to a cosmetic procedure. As such, it is a procedure (as well as facility fees and anesthesia costs) that insurance should pay for. Verification of benefits and prior authorization before surgery should be obtained. For patients without insurance, the surgeon's fee for a septoplasty can range between $1000 and $2000.
A septoplasty is frequently performed at the same time as the rhinoplasty. Your best bet is choosing one surgeon to perform both procedures. Even though the rhinoplasty portion of your surgery will be considered cosmetic, the functional component will be covered by your insurance and may decrease your out of pocket expense.