The Charleston MO. dealership is closed and has been for quite a while. The building stood empty last time I was by there. I cannot remember the name of said dealership but stopped by there on the way to Sikeston quite often. Sikeston was the epicenter of salvage parts and auctions. Hundreds of farmers and implement dealers passed by the Charleston dealer daily in route to Sikeston. Oliver had what I call a mini branch there, no doubt to show off their equipment to passer bys. Lots of new equipment on the lot and nearby field to show. 

One time there was a row of a dozen+ new 1655's there. They were not equipped with the 3 speed. We thought that was odd and asked the dealer about it. They were going to the Corps levee authority to be used to mow the dams/levees. The dealer said the mowing crews would just tear up the 3 speed so they ordered them without. 

So your 1900 Rice could have been sold by the dealership locally as there were some 6000 acres of rice produced in that area at that time period. (Now 200,000 acres of rice are grown in the area after alottments were lifted). The possibility exists that another dealer picked up your tractor at Charleston and it went further south into rice country also.