Thanks everyone!
At times, I think round pens show off the pure beauty of the celluloid better than the faceted pens. But if the celluloid isn't so special or the pen is black, then something else is needed to make the pen interesting, e.g. the shape (faceted pen) or the furniture (cap rings, clip, etc.).
Riccardo, I forgot to try to close the cap of the Extra to get the "Omas Extra" engraving to align better with the cap. I did it for all 3 modern pens, but I forgot the Extra.