Don't know much if anything about this model of pocket-watch.....but the movement is stunningly crisp and clean and seems like it has never seen the hint of moisture even......well done,and a keeper for sure!
The vast majority of Omega pocket watches from that era are nothing special and worth $50-$150 tops. What you have here is one of the very few pocket watches from that era in beautiful shape, in solid gold, with a dial that looks very nice indeed. Pricing it is hard but be aware that its a very nice watch.
Serial number indicates around 1912: http://chronomaddox.com/omega_serial_numbers.html Models were not well defined back then, so 18K Gold pocket watch is likely the most accurate way to describe it. Recent pricing is hard, you're just not going to find many like it to go off.
Value shouldn't be that hard to estimate. Go to a watchmaker and have them remove the movement from the case. Weigh the case on a gold scale. Convert that figure into troy ounces. Multiply by US$1,800 per oz., more or less. Take that figure times 75%, for 18K gold. That's the value of the gold in the case. Add another $100 to $200 for the movement (less if it not running) and that should be your total value. There's little collector premium on a pocketwatch unless it has a major complication, like a chronograph or repeater. Just the intrisic value of the precious metals in the case and a bit for the parts. Hope this helps, gatorcpa