This is indeed very interesting
@kaplan - I love it when the 'Omega anomalies' appear.
I was about to write:
"a C-case with a 1963 movement? - something fishy there"
However, if you do look into the ref number, there are a few come up.
A couple at Kaplan's
One at Bukowski's
One at Bonhams
All with similar serial numbers - i.e. one (the earliest) with 19,69x and others with early 20,XXX
All with what is considered to be the original Genta 'slimline' indices and hands.
All with only 'SWISS' rather than 'SWISS MADE' (I always thought this pointed to a US-destined watch but they have mainly been seen in European auction houses)
So, either the C-case was born in 1962/3 as the solid gold 168007, before it was thought to be released around 1964 as the 168.008/9 - or Omega kept a batch of 561 movements back to be used later.
There doesn't seem to be a reason to keep back movts as they were still producing these movts en-masse until around '66
There is an OF thread from 2015 where
@gatorcpa links to one of the Kaplan watches
https://omegaforums.net/threads/some-help-here-168-007.29397/
Bonham's and Bukowskis Auction house 168007s
https://www.bonhams.com/auction/198...tion-case-no624114168007-movement-no20950104/
https://www.bukowskis.com/en/auctio...-constellation-c-chronometer-wristwatch-35-mm
excerpts from Desmond's essay on C-cases
Edit
I should add that Omega have form with early 'lost' designs.
There is a pre-168.004 watch with a 5-digit case reference, whereby only a couple have come to light (and one of those happened to be Ringo Star's watch)