There is a difference between the flathead 6 and the V8 emblems, and the truck series emblems will have different numbers on them (D100, D300, D500)
The only picture I have of a 57 Dodge truck line up was taken at a poor angle. It has a D100 1/2 ton, a D100 Town Wagon, a D300 1 ton, a D600 Stake bed, a D900 dump and a C700 COE. The big trucks are at the end of the line and they are hard to see, but it appears that only the bumpers (some trucks in the picture have bumper guards and some don't) are different up to the D900. The CEO is a different critter.
The pictures of the 58 clearly show a difference between a D300 and a D800, but there are no truck sizes between the two.
A Google search for the front end view of a 57 D100 and the D400- D900 might answer your question better then this one picture I have. Gene
