You are right. I don't think it is a hiddenset. If you want 1" threadless, Campy does make the Chorus 1" threadless for about $42 at Probikekit.

FSA also makes some 1" threadless versions.

However, if you go from threaded to threadless, you will need a new fork, since your threaded steerer is not a good idea to use in a threadless setup.