I have a pair of front section flares that almost fit perfectly by using the right front on the left rear and the left front on the right rear. The edge that fits the bumper is almost perfect and used 124 front fenders are very common! Use 500E rear inner 1/2 panels to complete the expanded flare. This gives one a flare to start with that matches very close. Look at the front flare and see how much larger it is, then cut a template to match the curve.
You'll see that no one would notice the difference!

TobiasMB
4 MBs