Information Please - Ref 353.007

Hi All,
I am looking for as much information as is out there about a watch my fiance was given by her grandfather.

It's an Omega Constellation that he's had for many decades (not sure when it was last serviced).

It has been valued by Charles Grieg (Johannesburg, which i believe is where the watch was purchased) with the attached documentation. Ref 353.007 is what they have included on the certificate.

We have had it looked at by the Omega store in Brisbane (Dec 22), who didnt have a whole lot of information. They opened it up and found a Calibre 712 inside and dated it around 1973.

I havent been able to find one like it online, or much about Ref 353.007.

I was hoping somebody might have a bit more info or know where to look, as well as how much a watch like this might be worth.

Thanks

They usually say "gold value + a couple of dollars" in these cases.