I've never seen Duracoat or Cerakote sprayed thick enough to cover SN's. However, I don't think I've seen either on a real old gun with barrel wore like that either.
Sounds like you have a good plan, just keep an eye on it. One thing I wouldn't like about taping is you will then have a defined edge where the tape was. That is just something to think about.
Don't let your ears hear what your eyes didn't see, and don't let your mouth say what your heart doesn't feel