Crowns along with crystals and gaskets are probably the most frequently replaced parts of a watch, and so many of the crowns on the end of the stems of today's vintage watches are not the original factory fitted parts, which is why we see so many variations on Omega Constellations.
This has given rise to an ongoing discussion about 'correct' crowns for various models. While collectors are generally not too fussed about factory original crowns, there is a preference to have their pieces as close to factory specifications as possible.
Occasionally a debate stirs up over whether the decagonal crown is the standard for all Omega Constellation watches that fall within the first two design phases of the collection. I believe it is.