166.045?
If so, I don't see a light blue dial listed right now, but many of the original dials that were found on these are no longer listed. There is a darker blue/grey dial listed, but that's the only blue one I currently see Omega show.
Based on that one photo, it does not appear to be a redial to me, so if it is in fact light blue I would be hard pressed to tell you it's been refinished. Omega made so many variations it wouldn't surprise me if it's genuine. I can't say I've seen a light blue in person but I'm quite sure I've seen them posted before.