Hi Joe - welcome to myBulova. Great looking watch you've brought us. I agree with Stephen that it's likely gold filled and, for now, an unknown model to us. Our theory on the roman numerals are that they represent the last three of the original movement so we agree that the two originally belonged together and date 1930 ( we also believe that the first number of the serial is a year designator - in this case 1930). You're right about the content markings, there was no standard in 1930, most are but for some reason all aren't marked. Either way it's a dandy watch. I don't think it's a fake or a marriage of part, the dial seems to fit the case style and shape wise. Oh, about the 'open' marking - not unusual, I wish Bulova would have done that on ALL cases, we would see a lot fewer broken and bent hinges if they had!