No way, gotta be for one front seat unless prices have fallen DRAMATICALLY in the last year.
I've had covers priced at $500 each for the W108 (in leather) -- I ended up making my own. Vinyl "test" fit covers are currently installed, and look nice except for the rather "electric" blue.
Tour the u-pullit junkyards, interiors in fair to good shape aren't uncommon. There were two W116s in the local one, one with a decent condition MB-Tex navy blue interior last time I looked. Doesn't take long to strip the seat covers off if you don't want to take the whole seat.
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!