Hi, Hoipolloi,
with the provided information (pictures) the largest part is guessing only.
What I wrote above is only my poorly educated personal take.
Personally, I believe the chronometer printing was done at a later stage - if it were done when the watch was originally
equipped with this dial - it would be more than unlikely that the printing colour would've aged differently (like visible on your pictures).
And there are mor hints, but it wouldn't make much sense to discuss more about it, IMO.
But anyway, everything is more along the line of personal preference and what one would "like" to think about the story behind.
It could be an original (non chronometer) dial used as spare - the chronometer printing added later in lack of a full chronometer dial
in stock (would it be original? - would it be more original if the chronometer printing was added by an Omega worker and less original when added
by some expert in the Omega dial supply chain - even less original when added by some independent specialist ???).
Could also be a spare part dial sourced out of some NOS of once originally rejected dials (I've personally seen thishappen more than once).
Now, would this still be "original" ??
My initial answer was based on a very strict POV - I personally believe your pix don't show the dial/watch combination (aged of course) as they left the factory.
Personally and from a collectors POV I wouldn't have a problem though - it's a vintage watch with a lot of life (and service) history - so nothing wrong
with the dial.
Best is you go with the oppinion and experience of the real experts, i.e. don't believe me 
Best regards
Suitbert