Long delay, was meaning to get to this but I've had my 1D X hooked to my 600 II for the past several days.
The newer lenses (the ones you list, also the 40mm f/2.8 pancake, and I would guess the 24mm and 28mm IS lenses) have a firmware that can be accessed by the newer camera bodies (1D X, 5DIII, T4i/650D). These are the same lenses that report their serial number directly to the camera.
They don't necessarily have updates available for them - at this point, only the MkII supertele lenses and the 40mm pancake have had firmware updates, and while the 40/2.8 update can be downloaded from the product page on the Canon USA website, Canon didn't make the firmware update for the supertele lenses available - the lenses had to be sent in, at major expesnse for shipping + insurance, which I think was a bad move on Canon's part, unless they paid for shipping both ways (and I rather doubt they did, though I don't know for sure). Fortunately for me, my 600 II came with the new firmware.
To your question about what happens with older lenses, when you select the firmware item in the menu (which actually shows the current camera firmware version), you just get a message stating, "Memory card containing firmware is required to update." The screen you show is only seen with one of the newer lenses.
