Bulova 1950 Watertite

I bought the watch as a 1951 Watertite D model.  The case back has no date code on the outside.  The watch has the dial of a 1951 model Watertite.  However, the date code on the case back says 1950, as does  the date code on the movement (L1).  The case itself does not resemble a Watertite D model because the lugs are faired into the body of the case rather than look like the lugs are added on top of the case.  The movement is a 17 Jewel Swiss 10BCC which was used in the Watertite model.  Any clues as the model anyone.