Normal
My 2010 lived with the salt for years never undercoated I kept it clean and didn’t have a rust problem except for the cab corners . WTF ford the one was a three inch hole the other was a 2 no big deal I ran 1/2 tubes oversized one side and to the outside to the firs side hole and used silicone to seal and mount it to the walls . The other problem was the vibration damper. When it started to wear it sounded like a girl who bufarqee when you ride. You might want to maintain it or rip it out like some others did I kept mine and keep it secure and maintained the interior goes bad and needs redone.sounds disgusting .