Vintage Omega. Clueless!!

I recently acquired this Omega from a watch trade. I'm more of a Rolex guy, even though I do own the Bond SeaMaster. I believe this to be a re-dial, but again, not sure. It has the 266 movement, and a breguet numeral dial. What has me stumped is that on the case back there is no model number. Keeps excellent time and is a gorgeous watch. Just curious if anyone knows model, authenticity (I feel fairly sure it is an authentic Omega), and value? I appreciate any help!

Redial. Only the movement looks to be genuine. Omega logo was stamped on the case back by somebody, not by Omega.

e.g.