Any 14900 Fake Omega Constellation situation needs careful scrutiny since it is among the most ubiquitous from the photoshopped dog-leg lugged cases around. There is a little of the lull on eBay for some time however i see them sneaking back every so often, and it is difficult to say if another batch continues to be shipped in the Orient or it is simply the sooner ones being recycled. Never-the-less, careful attention ought to be worked out.
The most recent fake to come to light is proven within the capture of the current eBay listing. The vendor watches-n-such can also be selling an appalling “homage” to some black Constellation cake pan dial, most likely in the same source. In cases like this, the “n-such” being offered as NOS may return to bite watches-n-such within the posterior. 
While Constellations aren’t probably the most photoshopped vintage pieces with a lengthy shot (Rolex watch models in the 60s and 70s obtain that dubious honor), cases 14000, 14902, 167.005 and 168.005 in stainless happen to be specific with time.
If you are unaware of the inspections to create when assessing among the above models for sale, please review this essay.