Omega from grandpa

Hello there!
I have been given a watch from my grandfather who passed away, i soon realised i know nothing about it and would very much appreciate some help with the information i found in it and maybe some background about it. For context i live in Sweden and so did my grandfather.
The watch still ticks(?) and seems to be working fine but some age related dents and scratches can be seen.
I have no intention off selling it but an assessment of the value would be interesting.
I hope the pictures i provided will be sufficient if not i can try again.

Thanks beforehand! (and sorry for any potential spelling errors).

Thanks for info!
what does the SC stand for thats stamped after the five digits on the inside of the lid?

Overall. A nice watch with quality movement. Get a cleaning. Light crystal polish or replace.

Don't do anything to the case

Crown looks a touch worn, but leave it for now. Replacements are plated

DON

thanks and good tip i will look in to that !

another thing i have been woundering about is the lever with an A and R what is that and also the purple pearls inside do they have a function in the mechanics?
(apologize for probably very basic questions)