All cars sold in the uS by 1996 had to be fully OBDII compliant. Lots of cars got there ahead of time. The 202 chassis came out in the interval when the systems were being designed and it would have been real stupid to built a new car and then have to change it engine management system immediately.
As such the 202 got OBDII before all the other chassis. Since the E class changed in 96 nothing was done in 94 or 95.
Bosch Master, ASE Master, L1
33 years MB technician