Don't know what car that is but Dig's is blue.
I have checked the arches on the following. '72 450SL, '73 450SL, '81 280SL, '84 500SL and '86 560SL. On each one the top of the arch was rolled as pictured. The only one where the back arch was rolled was the 560SL.

To save grinding and welding you might try this.

http://www.benzworld.org/forums/r-c107-sl-slc-class/1468459-rolling-fenders-eastwood-machine.html