Omega 2300/3 (Wisdom Needed)

This was one of my grandfathers watches and would love to get it serviced/repaired. The crown doesn't wind forward but it does turn backwards.

I'm looking for any info on this piece at all from you Omega Gurus. All I know is that this says 2300/3 on the inside and was possibly made in the 40's?

• Should it have a rubber gasket on the inside?
• Are parts original? (seconds hand)
• is that blood or water damage on the dial?
• General history about this piece?
• Any info or thoughts on this at all?

I'm worried about where to get this serviced.

I greatly appreciate your time to write a comment, Thank you!

A nice model an worth to be "mild" serviced concerning the dial. IMO moisture led to rust of the hour hand (watch stopped at 4 pm 😀) .
Get the movement serviced - the hands cleaned (back-side coated with clear varnish) . I would not touch the dial.