If the contours are different, the covers probably won't interchange, although the entire seat will.
If only the pattern is different, chances are they will exchange. I'd sure hate to spend a pile of money on a set and find they wouldn't fit!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!