The N3 you mentioned is not a model number. It is a date code. N stands for the 1970s, and the 3 is the actual year. Therefore, N3 equates to 1973. If you want to know more, we will need to see what is inside the case. Bulova as a manufacturer was on its last legs when your watch was made. They folded as a maker circa 1976, although the name is still around, having been owned by several outfits since they folded. Currently they are owned by Citizen. A lot of modern Bulova mechanicals are made in China, so your watch is vastly superior to a lot of their latter day stuff.