1
Vintage Omegas get put up for auction on eBay all the time for low (as in ~U$10) starting bids. I picked up a vintage Seamaster (ref. 166.0209) from an eBay auction a decade ago for U$180 shipped - though I probably got lucky with that one.
If those movement and caseback pics are from the actual watch, I'd say it's genuine. The price, however, will probably go up as the auction winds down over the next 48 hours or so.