'97 E320 Has No Crankshaft Balancer
I don't think it does as it is a straight I6 configuration, not the V6 as was used in '98 and forward. I6 is good engine but has the infamous headgasket leak problem.
But you're right, get one made before 2000 as they took a lot of quality out of the car at that time ( at least that is what I see and feel).
Actually, a '97 E420 might be a good choice if you can find one that hasn't been abused.