Inside on the plate for the movement what is the number ?
The thin plate has a number to ( I D ) The movement.
Majority of the C230 etc., models are about the same so it should not matter to much. They are .... " Inter-Changeable ".
I have found that many are switched around in them. Maybe when they were replaced or re-done at service time.
Check it out, but be very careful removing the case back sometimes it is glued real good and the gasket O-ring breaks.
Be sure when replacing it back on that you tighten them with a ..... Cris-Cross pattern so as the case back cover wont warp.
Like 11 oclock oppsite 5 oclock / 1 oclock opposite 7 oclock, and so on. Make sure the O-ring gasket sits in the groove real good.
And do not over glue the O-ring as to get Silicone into the movement also.
Removing the crystal is easy, if need to re-seal it. But don't remove the gasket if not needed, just re-silicone very thin and a little.
Also be very careful if you remove the (Crystal) it has a ( Nylon Gasket )that is very (Fragile).
If it is sealed good do not remove the Crystal if you don't have a spare gasket on hand.
If removed use a press very gently to put it back.