Tex d guy,
Cummins has alway used common rail as far as I know.
As you can find out by reading any Diesel engine book from the 50's or the 60's.
There are 4 common injection systems used on diesel engines.
1 Jerk pump-multiple pump system. (Like the old Cat engines)
2 Unit injector (like the old detroits)
3 Distributor (like you see on GM 6.2 diesels)
4 Common rail, of which the "OLD" Cummins system is
and using what they called the pressure time principle.
The common rail system has to be regulated by controlling the rail pressure. In the old days the common rail systems had no "electronics" to control them in any way.
So just because "electronics" does not exist on the system it does not mean it is not a "common rail" system.
Lastly, if the injector is independantly metering the fuel, like most electronic injectors do. They would be in the number 2 classification of "unit" injection.
In true common rail the injector just injects fuel and has nothing to do with metering. By metering I mean controlling the volume of fuel required to maintain a certain power level as commanded by the governor.