The distributor housing, points, condenser, rotor, and cap were the same for all engines. What generated the different part numbers stamped on the housing was the many different combinations of advance cam, weights, springs, and vacuum advance can.
There were many other 1969 distributors that had a longer slot in the cam than the one in the 480 distributor, which provided more maximum centrifugal advance in other applications - see the detailed distributor specs chart in the back of the 1969 Chassis Service Manual.
The 480 distributor just happened to be the part number assigned to the Z/28, with its own combination of cam slot length, weight configuration, springs, and vacuum advance. Other than how those elements were combined in the 480 distributor, there's nothing "special" about it.