I would guess that the case is American-made, which means that there is no Longines reference number associated with it. Maybe the movement is a caliber 10L.
Approx 27.3 mm without the crown. Sorry for my five words, I’m just a beginner ☺️
Just gold plated
Approx 27.3 mm without the crown
According to the cb, it's gold filled, meaning a much thicker gold layer. I'm not an expert on military watches but never saw a military watch with such heavy gold coating (except for some dictators here and there).