In some cases the "build date" by itself will not tell you what year/model it is. For example, if the bike was built after September 1972, it would probably be a 1973 model. The missing VIN plate would solve the mystery, because Honda put "197x Model" on it.
Unfortunately, in most of the data available, Honda lumped the 1972 and 1973 models together. Only 1974 is identified separately.