I have an F100 which is missing the eyepiece "cover" (circular rubber part which protects eyeglasses/eyes). See photo.

I tried a DK-6, but don't see how that can be attached- there must be another part used with it.

Having guessed wrong once (and not wanting to add to my collection of strange spare parts), I think I may need Nikon 2927. I suspect that will screw into the inside of the metal eyepiece frame. But before I order one of those, I'd appreciate it if someone could confirm I need a screw-in eyepiece, and whether #2927 is that piece.