[Colonel Kane]

Would you really need a sector/ world code? I'm, each shipyard would have its own code and no two shipyards should have the same code, though it could be possible in a interstellar government. I seem to remember reading somewhere, that airplanes in WWII use number based on where they were manufactured and what year.
Bottom line is it is your verse, do what you think is right. I could see where there might be a need for sector and world codes. Look up VIN numbers for vehicles. 17 digits long, telling where it was built, which manufacturer built it, which plant it was built at, as well as the serial number of said vehicle