Jesse was told by Col. Wiman that the Model D he was using to make the crawler would be discontinued so he went about designing tracks for the GPO. This model was better suited for the orchards of the Yakima valley, they built about 26 before Deere stopped producing this model of  tractor. If you notice that in a lot of photos there are some with and with out fenders. Jesse told me that every GPO Crawler were shipped with full fenders but using it in the orchards they would fill full with trash, when they would take them off to clean it out they were never put back on.  If you look at the last photo on his page you can see why they did it. It is really too bad none of them have survived.