I admit I'm new to Omega. I found a very pretty watch on eBay, but was a little put off by the lack of observatory-and-stars medallion on the back of the case. Before I make a bid, can anyone render a reasonably informed opinion about the authenticity of this watch from the pictures the seller posted? (btw, I really dislike the 1980's-style glob-o-metal around the case that I see in 90+% of this model of constellation; for my taste, this design is much more elegant and it's giving me a bad case of the musthaves):

Thanks in advance.

 

Thanks for the input. I went ahead and bought it. It's funny, because the internal debate for the last month was "is my first Omega going to be a Speedmaster or Seamaster"? That answers that question