I remember to have seen a package some months ago, sadly only for FSX though, that transformed the default DC3 in a Super DC3... or maybe used the default to extrapolate a Super DC3 to add side by side to the default... can't recall correctly.
Not much more I remember beside it was... I think on Flightsim.com... should I be wrong though it would be either here or AVsim and nowhere else.
Mind that I have no idea if the exterior model is any different than the default DC3, though (
the Super Dc3 had retractable tail wheel and completely covered main gear in flight to give it slightly better cruise speed and range), but seen it was free you can always try it... if you use FSX. If you use FS9... I feel your pain. I would have liked it too.