Anyone recognize this?

This watch was inherited from my dad; it was in a real state so I sent it back to Omega in Switzerland to be refurbished almost 12 years ago. At that time I wasn't into watches so I didn't ask for any details on the model, just happy to see it restored to a fantastic condition, probably at a far greater cost than the watch is worth!

However, I do now have a watch collection so am interested to understand the history of this one. I know my Dad bought it in 1970 +/- 1 year (so officially hit 50 yrs), and I know the Omega centre in SG tried to buy it from me when I wanted it restored, which puzzled me at the time since it had a green mouldy face, super scratched glass and quite plain!

I'm asking on this forum, because I currently live in China and definitely would not risk parting with it to get it authenticated; and due to COVID I can't get back to the UK.

Any insight into the model etc., would be greatly appreciated.

@padders Yes, it's not auto and I'm certain the dial was replaced, the original was unsalvageable! Not sure the hands were though. Does it have any name, or just that model number?

Do the 136.041 and 166.041 share the same case? Except the case back which is deeper for the automatic? Does anyone know for certain? Thanks.