Why not just email a copy of the letter to the insurance company and let them answer if they sent it so you know if it is a scam or not? You posted a copy for us, so you apparently have a scanner or some means to send them a copy.
As for the age of the car, you wouldn't collect enough if it was totaled to justify the collision premium, and even if it's a minor repair, like a dented fender, you first have to meet your deductible, then the balance of the repair would almost surely be more than the car's book value, so it's still totaled for insurance purposes.