Good question Bob. I have several Gemmer steering boxes for C's in the shop and several Ross steering boxes for B's out there also. I have one Ross for a C that I rebuild here at the house but did not compare the parts when I had them apart. I have a C at the other place that I think has a Ross box but I will not get out here to mess with for quite some time. It won't help now but when I get to it some year I will remember and take pictures.
The Gemmer and Ross boxes are very different.