Yep, even the ones available at the dealer need to be retrofitted.
You need a dremmel motor, apparently, but I gather it's not too difficult to do.
In fact, Hi-Power, Placo1, and myself are going to purchase and install this Avantgarde (S600) grill on our W124's together.
When we do, we'll post the installation process for the benefit of everyone.
Also, I'm going to order the Zebrano Wood / Black Leather steering wheel for my W124 at the same time. It's about $400 for the steering wheel, but it'll be worth it. Those wood / leather steering wheels are pieces of art, and my black leather steering wheel is shot.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".