Zenith A386 Tachymetre Scale

There are two common tachy scales for the A386, but only one that is original to these watches.

The easiest way the difference between the two:
the original tachymetre has an elongated “C”, whereas a service tachymetre scale has a rounded “C” (more shaped like a circle).

Zenith A386 Tachymetres
Zenith A386 Original and Service Tachymetres