A typical demountable and glass office partitions assembly rates around STC 38. That lets loud speech through, so it is often worth upgrading between bedrooms, offices and meeting rooms.
Most effective upgrade
Specify acoustic-rated partitions with double glazing and seals, and close the plenum above.
Acoustic panels on the surface add only 1–3 STC points. They are for the sound inside the room. See STC vs NRC and flanking paths.