I got to nosing around my 1995 E320 this evening and found the A/C dust filter. It is a pain to get to (Honda has them beat in this regard). The car has 88,xxx miles on it and the filter is filthy. I did not have any to replace them with so I just tried to clean them up some. Just for everyones information the MB P/N that I got off of them (there are two) is 124 835 00 47.
Be careful when removing the plastic pieces that have to be removed to access them not to break any of the tabs off.