No, the replacement harnesses are fine.
Mercedes got caught up in the green movement, and experiemented with wire insualtion that would be more easily recycleable.
The problem is, it bio-degraded in the car, due to heat.
The insulation was fixed at the end of the 1995 model year.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".