Agreed, those are the later version of the Bridgestone cast lugs. However, the S/N format is not Bridgestone. It may not be a Submariner. There appears to be corrosion on the main tubes and the top tube brake cable appears to use brazed-on stops, as opposed clips. If so, this indicates hi-tensile steel, as opposed to the stainless steel of a Submariner. However, this is easy to check with a magnetic. If the main tubes are magnetic, then it would be a Skyway (either Bridgestone or Kabuki branded). Based on the serial number, it should be a 1977 model, though the first two characters are reversed from the Bridgestone format.