My latest watch purchase gamble for £150

Hi guys,
This is my latest gamble. Bought this watch for £150 without seeing it in person. The pics are really poor and from the seller so I apologise. What exactly is a Omega Non Magnetic watch? Not much info online about that for watches this age. No info from seller on the movement and when I asked the size of the watch the seller told me “man’s size” haha. Anyone like to tell me what this watch might be based on this limited information? Will update this post with more pics and pics of inside once I take delivery to see if any of your expectations or assumptions are correct if you are interested. For all I know I could open this up and it’ll say Casio. The lugs attracted me to it. Would they be considered “spider”?

An omega chronometre of this era could contain a 30T2RG movement...very, very nice score if it is...

Will update when I take delivery and see if it is. Whats the background to the non-magnetic branding? Ive seen it a few times on a few old omegas but does that make their construction any different? Thanks for your knowledge 😀

So as promised an update on my £150 gamble with new pics. Watch arrived today. How do you feel I did and is the crown non-original? Everything else seems to be original and matches up on the Omega site. Missing the case screws for the movement though!

Pic of movement out of case showing crown.

Movement very clean. Crown replaced. For what you paid is a nice watch.

Worth what you paid for it or a little more. Not impossible to find a clean dial. I had one of these ages ago and this movement is seriously reliable and easy to service. Enjoy mate!

Thanks for all your advice. I intend to clean up the dial. I’ve been having a go at cleaning dials recently and my results are in another thread.