Gold Heuer Carrera - unique?

Hello fellow TAG / HEUER owners and enthusiasts.
My late father was a collector of vintage / retro pocketwatches and watches and amongst his collection he had a "well used" Heuer Carrera which he used to wear and which I think is 3rd Generation "Barrel" case, Calibre 12 or 15 movement with a Cotes De Geneve dial?
Possibly a Carrera 1158CHN but the dial is different in that the "12 noon" is a single point and the "9" and "3" do not have luminous dots but a straight black line instead? The case is slightly dented in several small areas showing how soft the gold metal is and the glass face is damaged.
The black second-hand sweeps majestically and silently and is wound up by wrist movement apparently.
It has a MONTAL rolled gold band strap (not original I'm guessing).

I would be grateful if anyone could advise what "model"/ year etc. or whether they are aware of others still in existence?
Many thanks - photo attached.

Nice find. This would look great after a little TLC, maybe on a black strap

Many thanks for your research and answer abrod520. I should have paid more attention when my father was setting up his watches / clocks / pocketwatches ans working on them and should have asked him to tell me where / when he bought them etc.
Just saw a programme about Nicholas Parsons and the Breguet Marie Antoinette pocketwatch and I now understand my father's fascination with the internals of timepieces!
Thanks again.