Most new model watch sales on Ebay are legitimate. I have bought a few watches from the site and haven't had any problems. I think the problems are more prevalent with vintage watches in which it is difficult to determine if all parts are original and it is a little easier to sell counterfeit older watches. I only buy stuff on Ebay, watches or other goods, from sellers that have 100% satisfaction rating and have quite a few sales so there is a good history. Obviously you are always taking some risk buying online but with good pictures and good background on seller you should be fine. Good luck. Nice watch.
Stewart