Active CC (i.e. radar controlled) was available as early as the E38 7 series (1995-2001, not available on all model years). Those early systems did not have stop-n-go functionality. I have found that the option is rare no matter the BMW model.

I have even investigated retrofitting the feature on one or more of my BMW's and ultimately could not justify the cost. By the time you purchase the control modules, radar, grille, control stalk, clock spring, wiring, etc, and (sometimes) brake components and instrument cluster, it gets costly fast (and this assuming buying all parts used).