I believe 1980s India is the correct ID.

Bead release compound refers to products used to coat mandrel wires prior to working with molten glass over a torch or lamp, what is sometimes called lampwork. Release products can be white in color such as kaolin or alumina, red clay, or black carbon.

Bead made in Venice typically were not made with bead release on the wire mandrel. Instead the glass made direct contact with the metal. An acid bath was used after production to dissolve the remnants of the mandrel. The resulting holes are very clean.

Beads from India used to be commonly made with black carbon release. I think that is what is inside the holes of your beads.

They later began using white release products. You might also find red clay inside the holes of beads from India.