Different box entirely in the w210
anV6 would have had a four, or possibly five speed auto with standard and economy mode. On the 300E and 300Dt the four speed auto was standard, the manual a very rare no cost option, and the five speed auto was a cost option.
The confusion over the TC is in part because the switch isn't marked as such. Basically it is fitted with a form of TC that, like the Omega, is run via the Abs ecu. It isn't designed to be turnoffandonable, but the system plays havoc with tyrechains if used. So Mercedes, in their infinite wisdom fitted the car with a snowchain switch, which is the same as an off switch only they cannot call it that for fear of misuse
Making TC optional or not is purely down to development... If it's an option people might not order it, but if they do, then you keep it a cost option, and if they don't order it, you want a while and give it away making yourself look good...
It may not have been an option on the manual cars though as you have a clutch to control torque
wouldn't worry if it's not fitted though