Doublestamped vs single stamped Chronostops

Hi all,

I have read that the 145/146.009 are the standard dial Chronostops, while the .010 are the driver/90* rotated orientation. That being said, it seems after a point there double stamping was the norm, and normal configurations are stamped 146.009 and 146.010.

I have recently purchased a '69 chronostop date (920 mvmt), and while it looks solid (lightly polished but some brushing still visable, generic domed dial (NOS is in the mail)), the caseback is stamped 146.010, which to my understanding was only for driver orientation.

We're there some standard orientation that were stamped 146.010, or is this the caseback of a driver?

And yes, the lume dots have fallen off, but a service is in the works to ensure there is no particulates and I do not plan on reluming.