ok dont overthink this. remove the bolt and pulley. inspect the keyway it will still be in the crank. inspect the keyway slot in the pulley. it this is all good inspect the rubber elastomer on the pulley . look for bulges or rubber sticking out. if it is new pulley needed. if not reinstall the pullay after installing a new crank seal. you have it off so do this as a preventative leak measure. torque the pulley to 150 ft/lbs + 90*. this is not easy! use the proper crank pulley tool and a cheater pipe after the intial torque is achieved. drive the car 100 miles and retorque again.
if you require a new pulley go to oediscountparts.com that is skyland automotive in ashville n.c. mercedes dealer with the cheapest parts out there . 260$ shipped
do something generous for a stranger as luck has shoved a horsehoe up your ace!! this could have been a very costly accident to your engine