If this is the rear control arm then probably not, the leveler is on the front control arm.It´s for headlights leveling. It adjusts your headlights when weight is applied to the car so that you will not blind other drivers i think.
Looking on realoem I don't see anything quite like that thing for my model. Recommend looking up the rear control arm assembly for your model to see if anything comes up.
BMW parts 3' E46 330i Rear axle support/wheel suspension
EDIT: Looks like I might be wrong about the headlight leveling only being on the front suspension. The part may be the "Regulating Rod" from this diagram.