As far as I'm aware all bass strings have both core and winding.
It's only guitar strings that are core-only on the smaller ones.
'80 Rick 4001. '84 Fender Power J Special, '05 USA Jazz, '11 USA Precision, M Miller Jazz. Peavey T-40, Zoom B3. GB ShuttleMax 12.0, GB Uber410, fEARful 212.