Kids I put the screen at .218"
Forgive me but did Wacom come out with a 12.1" screen?
And no I do not think there is that much metal in an LCD screen.
Wacom "tunes" there tablets to different thickness. They also map out interference from the surrounding shell and electronics.
You will definitely want to use an overlay on the screen. Thin plexy or Lucite, but believe it or not glass could also be used.