If the Gemmer you have was manufactured for an Allis B, C, or CA it will bolt in fine as all torque tubes were the same as far as how the steering box bolts fast. It the Gemmer you have was for a C or CA then the cross shaft would be larger would turn the oposit way you turned the steering wheel. The small end would not have the ball on the end and the splines would be larger and machined different. The shaft would also be longer but probably would not be a problem in it self.
If it was made for a B you would not have a problem.
I will wait for your pictures.