The "Job Rated" emblem on the grill of the Pilot House Still remained, it even carried on at least the through the first body style of the Functional Design trucks, about mid way through the 1955 model year. The Job Rated classifications were real popular with the Soldiers returning from WW2 and Korea. Though the company may have changed the classifications of the trucks, the Soldiers coming home were still looking for the Job Rated, so Dodge wisely kept putting the emblems on.
You will find few things on the 30s through the early 60s Dodge trucks had a definitive start and stop date, as innovations came along, they were installed on the trucks as soon as the parts became available, and those change overs could begin at a different point at each truck plants. Dodge didn't wait until the new model year to begin the new innovations.
Gene