Here's the Tech Specs page, which is slightly more hidden: https://www.apple.com/iphone-duo/specs/
Notably, the inner screen has a nano‑texture finish (which Apple normally upcharges significantly for), which implies it is glass.
Notably, the inner screen has a nano‑texture finish (which Apple normally upcharges significantly for), which implies it is glass.
I haven't looked, but am guessing the probably exists on other Apple specs pages.