I think what you have there is a Lemania 1276 movement, often found in Tissot chronos. Details here:
http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Lemania_1276. The absence of a signature on the movement makes me doubt it belongs with an Omega dial, which I am anyway suspicious of as it's very clean and the hands look too early in style. Hard to tell from these low-quality photos (another bad sign) but I suspect it's a Tissot redialled as an Omega. Whatever it is, it is highly questionable so just forget about this one and look elsewhere.
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