The specific model (reference) number for your watch should be located on the inside caseback. A watchmaker can remove the caseback and provide you with that number if you want it.
According to this 1977 Omega advertisement, your watch originally retailed for $1800 and featured ".
..a 14kt yellow-gold bracelet and case with 50 diamonds encircling the round, lapis lazuli dial." It came from a collection that combined ".
..lapis, coral, onyx and other stones with the flawless craftsmanship of Omega."