Well if it is a new 45mm 8500 it looks good. But the source is important too. Are you buying remote or in person?
Like I said it looks good, but you should have no trouble having an Omega Dealer look at it in a city as large as yours, good luck.
Its fake, the movement is the giveaway, the Cal 8500 has the geneve waves decoration on the rotor, AND on the movement, your pictures do not. The Cal 8500 is meant to have a full balance bridge, your pics have a simple balance cock. Do not touch it!
Also the displayback is too thick, the helium escape valve is on 10 instead of being above 10, bracelet diving extension is wrong as well
Doesn't the valve appear at 10 on these 45mm models? Regardless, I should have been paying more attention to the back/movement Bad job from me Here is a real shot.
Some of these DO have the HE valve at 10 - chronographs are the first that come to mind as well as the larger ones. Ashley made a couple good points about the movement. The rotor hub isn't right either. I'll give Steve / Cicindela a pass because he's primarily a vintage guy.