Does anyone know what these are called? I remember seeing them advertised on a sportsman dvd or something and getting some gifted to me as a kid. Had a replaceable soft body and a hard head

A jig. More appropriately, the lead head molded to the hook is a jog head. Places like netcraft sell old time molds to make your own by melting lead. All my jog heads are old, 70s through 90s and are made of lead. They’re widely used in many sizes in fresh and salt.