Bah to non-functional silly keys! I have a functional "Any Key" for a Model M.
Many years ago Hooleon sold replacement key cap tops for the Model M with extra printing for DOS Wordperfect, Lotus 1-2-3, and other programs I don't recall. When I requested their catalog they sent me a sample keycap labeled as "Any Key" and has their name and phone number on the front edge.
I also still have a set of the WP5.1 keycaps.
A minor annoyance was that they didn't fit as well as the IBM originals; they're not quite deep enough it seems.