As fake as one can possibly fake a watch.
There is absolutly nothing 'Omega' about this watch. Everything is wrong.
On the contrary - the watch is correct in all its parts down to the second hand and crown as far as the photos can tell. See "edited" below...
Numbers are in the correct range. Engraving on the outer side of caseback is fine for this period of production.
The number 136 on the inner side of the caseback is also found on the underside of one lug which is perfectly fine and proves that the case parts belong together.
The only thing that might have happened: Maybe the dial has been swapped (allthough this is perfectly original and not reprinted). the wide gap on the edge makes me think about this possibility.This "view" could also be caused by a missing bezel (see edited below). But also could be totally legit as is...
Edited later and to correct myself:
The stepped bezel seems to be missing on this "Naiad" model. Therfore I would like to see a side view of the case. This must be checked... But the parts which are present are original.
I assumed you know a bit about Omegas.
So I wonder about your statement:
"
Would have to be fairly early to not use the beryllium copper plating."
Where did you learn this?
Omega
never used a
beryllium copper plating! Omega used rose gold with different percentage of gold content.
1) The early variant had very little gold at about 3% only, the main component was copper at about 85% plus about 10% silver. So we might call these movements rose-gold plated or maybe better "copper/gold-plated". This coating was prone to oxidation and sometimes the surface looks almost black due to copper-oxide. This plating was used only for a short time as it failed the protection against oxidation.
Omega very soon changed the plating to variant
2) the percentage of gold wass raised up to 80-90% with only 10-20% copper remained to achieve the red/rose colour.
Hence these later rose-gold plated movements can be found still shining as if they had left the factory yesterday.