I've done some research on this and the dust pollen filters were added in the 1994 model year.
Also, r134a was added in 1993 on the 300E, and I've seen several 1992 500E's with r134a.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".