I suppose it could be possible if it was a later steel wheeled tractor, but the early ones were 4 speed only. They had to change the rear end to accommodate the 5 speed. An easy way to tell is if the shift lever is straight, then it is a 4 speed and if it has a curve to it, then it is the later 5 speed. Another way is to look at the front of the transmission from underneath. The 4 speeds had a tin cover over the pinion shaft, and the 5 speeds had a gear there with a cast iron cover, and then the steel cover on that.