What do I have here? ID help

hi all,
Need help to ID this watch. Belonged to my grandfather and was passed to my older brother.
He died a couple of years ago and now I have it.
Crystal is in terrible condition but I can make out Automatic in the top half and Seamaster / Calendar in the lower half.
Given that this watch has had a hard life and there is no wearing off of the gold plating makes me think the case is 14k gold.
All help appreciated.

Looks like a omega seamaster calendar reference 2849.

Here is a link with more info: https://www.omegawatches.com/vintage-watches?reference=2849