Hmm, by "curve" do you mean a type of moving script, a actual "curve" marking, or a type of floppy ear?
If you need a scrolling code, just use the scrolling script on only the right/left side of the head.
If you mean a marking, simply just draw a curved line if the bottom circle of the F/C head UV.
If you mean one ear with a floppy ear mesh and the other just normal, I'm afraid that's not possible without modifying the source code because you'd have to edit it to tell if what mesh to put on the head mesh/skeleton. Someone correct me if I'm off there, though. You could try using the transparent script and just edit one ear, but your probably not going to get a "curved" ear look.