Omega Constellation 711 vintage 18k help

Any one knows this watch? Bought in1973

Firstly, the automatic rotor is not present unless you or someone has removed it. Do you have it?
Secondly, the gold hallmarks (not very clear from your image) seem to indicate that the case is a locally made one for the imported movement, which was a standard practice years ago to avoid import tariffs in the country of where it was sold . If it was a Swiss made case you would have seen "Swiss Made" stamped in the back with the Helvetia logo often found as seen here .