Ok, I just said to myself, I should call the butcher and bother them. They said they won't take the time to take off the silverskin off the back straps, due to damage to the meat. But they said this is the tendon that connects the back to the neck and said some use this for primitive projects.
Glad I got it figured out. Still don't have what I want. But after drying it and tearing it into quarters, it seems like will work for wrappings and such.
Hope mullet still wants it.