Thanks! Perhaps my terminology is inaccurate. The stichting looks different to me between the shell and calf versions. The shell version (http://www.allenedmonds.com/aeonline/producti_SF2291_1_40000000001_-1) seems to have a ridge on the top of the stitching, whereas the calf version (http://www.allenedmonds.com/webapp/wcs/stores/servlet/producti_SF2201_1_40000000001_-1) seems to be more flat.
I believe this is just because shell is thicker. That's likely the closest they could get them to looking the same.