Phelps-Dodge used to make their Romex with a black or light blue outer jacket in the 70's and early 80's. Cadillac Cable made their jackets in green or brown. I guess manufacturers have the opportunity to color their jacket to make their product more recognizable.
I have also seen some manufacturers who made 8/2 and larger have black and RED conductors instead of black and WHITE. I guess that's because it's not likely that there would be a need for a 40 amp 120 volt circuit.
The paper-wrapped ground wire is definitely indicative of Romex or more specifically, NM cable.
