The truck I have is a 1950 1-Ton. It has 4 of the cross sills shown on Mar-K site plus the rear cross sill. My bed does not have a different style front cross sill, the first sill starting from the front is only about 6" from the front bed panel. I'm not sure if the 9' bed you have from 1953 is any different, but I wouldn't think so. The front bed panels are different from the 1/2 & 3/4 ton models also, they are available. Hope you are able to get everything you need for it, those 9' beds are a good draw at a show, many people have never seen them before.
Tom