Thanks. The movement looks fine to me - often these were not marked Omega anywhere on them at the time this was made, but the cover over the coil has the correct movement version on it (1444), and the wheel train bridge has the serial number on it. Using that serial number, you could get an extract showing when it was made, where it was delivered to, etc. if you wanted to pay for that.
The gold bits on this watch are solid 18k gold. The diamonds in the bezel are listed as:
Clarity : IF-VVS
Colour : TW(G)
Diameter : 1.500 mm
Shape and cut : 32 / 24
Weight ( Ct ) : 0.0121 each (x38)
Value on something like this is difficult, partly because it's quartz, partly because these Constellations are not collected like older mechanical versions are, and partly because it has those diamonds. The style is somewhat polarizing with people, at least from what I've seen, so if you are thinking of selling it, you would have to find the right person I think.
If you need a value for insurance purposes, then the information I've given you should help get an accurate appraisal from a jeweler.
Cheers, Al