On page 76 of The Catalogue, at frame 43 I picture a few Skyline Press Clip Oddballs, and the demi-sized pencil below is the fourth one from the right. Now that I've found a full-sized example to go with it, I don't quite think it just a fluke anymore:
These have no trim ring at the top, like the Press Clip IV, but they have a middle ring, like the Press Clip II.
Since these are the only two I've seen, I have no idea which top button is correct, but I do suspect that the colored plastic tip is.
That makes the fifth family of Skyline Press Clip trim configurations. Shown below, from left, are the Press Clip I, Press Clip II, Press Clip III (January 12), Press Clip IV (April 4) and the Press Clip V:
And here's a better family picture. Anyone got a full sized III?