What year is your car? 1973 models still have the "Euro" blade bumpers without shocks. '74 - '76 cars have redesigned fenders that work with the shock mounted bumpers (and blades, too).

FWIW, I've observed three versions of fenders for W115: Two early style for blade bumpers only ('68 - '73), and one for '74 and later cars that came with blades or shock-mounted depending on market.