Chrome or Black Finish of the Nikon F Body

Synchro Selector Ring (part 20FB1-2303)

Early black bodies are having a synchro selector ring with a black base. Since today I have recorded black bodies between number 6400825 and 6421887 showing this feature. From this onwards the black bodies also have an all chrome synchro selector ring.

Example: 6404353.

Remark: some early black bodies are found with an all chrome ring, e.g. 6414923 and 6418323. May be it was exchanged for some reasons?