Questions about Omega Seamaster 120 166.027

Hello everyone, I have a question about the Omega 166.027 watch. I inherited this watch from my grandfather. I decided to have it serviced at Omega and they tell me that the glass is not original. However, my grandfather doesn't remember changing the glass. Is this curved glass with magnifying glass official?
I ask the question because I see that other Omega watches with the same reference are sold on the internet sometimes with the magnifying glass and sometimes without the magnifying glass.
Here are some examples :
https://www.stetzcowatches.com/product/1967-omega-seamaster-120-baby-seamaster-37mm/
https://drouot.com/en/l/18909860-omega-seamaster-120-fecha-con-lupa-referencia-16600027-br
https://omegaforums.net/threads/vin...27-with-1098-540-simon-freese-service.159272/

Here are the photos of my watch:

Thank you for your help !

My grandfather bought it in the 70s in eastern France. Apparently, he never had the glass changed. It's true that it was originally a different bracelet, but he chose to put this one on to make it more practical. The watch will be back from service around April 2024, and I'm going to choose a black leather strap, I think.