What time is it? Watches and horology

Selling his Omega to buy a Titanium bike frame.. :)
http://www.ebay.co.uk/itm/Omega-Seamaster-Chronograph-Automatic-8-Months-Old-/220839595985?pt=UK_Jewelery_Watches_Watches_MensWatches_GL&hash=item336b10cfd1

He says it includes loads of original stuff but is there any way to tell these ebay listed watches are actually genuine? I fancy one of the Omegas

That looks as sound as a pound.
Generally you buy the seller, not the watch. The pictures show an absolutely genuine Omega, with all the right boxes, books, tags and cards, the serial number in the right place, a nice smooth polished look to all the edges (fakes usually have sharp edges) and the dials and date window in the right place (impossible to fake if you're not using the correct movement) and the small seconds counting down and the large one at 12 (the large second being the chronometer seconds counter, not the time one),again impossible to fake with the wrong sort of movement.