Given my experience with my insurance company here in California I expect that the insurance companies will fight this tooth and nail. It might not be with a flat denial, but they can make it effectively impossible by requiring endless paperwork, endless internal approvals, and by causing endless delays. In California it has been the law that they have to cover us and yet I still had to file a complaint with the state insurance board to get my insurance to cover some of my therapy. Once the state board got onto them their tune changed pretty quickly.
From what I have read this kind of treatment of trans customers by insurance companies is not unusual.
If you can get your insurance company pay for your surgery I think that it would happen only be after a long, protracted, nasty fight. I hope that i'm wrong but knowing how slimy insurance companies are I would not be surprised if they fight this with underhanded tricks.