The Gullwing is the nick of the 300 SL, not SLR.
After succes in motorsport with the 300 SL, MB needed a replacement, thus the 300 SLR, meanwhile M. Hoffmann convinced MB to make a street legal SL witch is the Gullwing we all know and love.
Also the curent SLR isn't really reminescent of the 300 SLR. Heck you can find more design cues between the Z4 Coupe and 300 SLR than between the actuall SLR and the true one.
Also the actuall SLR is really more of a GT, while the 300 SLR was a toroughbred sport car, created for the sole purpose of deafeating Ferrari and Jaguar.