What have I found here? Omega with R17.8 SC movement

Hi,
I have found an old Omega watch and have some questions.
I bought it, because it is running (needs a service) and because of the nice patinated dial.
Before buying it, I did not know the movement.
After I got this watch, I have opened the case back and saw....I think, it is an Omega R17.8 movement.
It is a square movement in a round watch.
The diameter of the watch is 30mm without crown.
Today on the small side, around 1943 a normal size.
It has a screwed case back!

My questions:
Have expected a refencenumber inside caseback, but there is only a number (I think, it is a kind of movement number to date the watch).
The original movement number is older (think, the square movement is 2-3 years older than the watch?).
The hands are correct? Saw this second hand often, but especially the hour hand could be thicker than others, I have seen.
All the hands are blued!
The crown is a little too big? (saw very similar crowns on other old Omegas).

Thanks for your help.

And now some pics:











Thanks in advance,
Peter

Hi Peter,

It looks like a CK2300

(here's mine)

Same case, I think.
But some differences.
Possibly, my hands were relumed at some time in the past, but the shape of my hands seems a little different.
But it should be an Omega of same time.
Your 2300 has a 17.8 movement inside?

Yep - the case is a CK2300, it has an R17.8 inside, which has the same OXG import mark as yours, denoting that it was expected to the USA.

mine came from the son of the original owner, who bought it on a trip to the US during the late 1940s.

Yes, I have tested it with UV.
The hands are fading out slowly, the numbers very fast.

...with a small part of a tablecloth under it (try to hide in pics)...😉