Hey Ed,
It seems that the Kaiser Willys Corp. liked their design so well they didn't change much from year to year making it tough for us to identify what years they were produced. :lol: Here is what I got from the good guys at Willys America:
As GoJeep said from '46 - '50 1/2 they had the flater grill, flat (no rib on top) fender and thin profile hood (at the radiator).
'48 thru '50 had a stainless steel "t" bar grille trim. The hood had the script "jeep"station sedan". From '49 and on the 4x4's had the script "4 Wheel Drive"
Starting in mid '50 they had a styling change that included larger grill with 5 horizontal chrome bars, the fenders have a rib on top and the hood has a thick rounded profile (at the radiator).
In '52 and '53 they were the same but now have the 3-winged hood ornament which are used on the station wagons only. The hood gets a horizontal chrome trim on both sides and so does the cowl.
'54 and '55 the changes were only that the grille now has 3 chrome bars; top, bottom, and center.
'56 grille changed the location of the chrome bars to top, bottom and up one from center. The stainless steel trim now goes from grille to taillight.
'56 1/2 and '57 was the same but they added the 4" hole on the passanger side of the grille for heater air intake.
'58 thru '64 grille went back to the 3 chrome bar locations of top, bottom and center. They also re-shaped the front turn signal to 2.5" dia.
I hope that somewhere in all that you find the answer to your question. The trucks have a few differences, mainly scripting.
Good Luck,
Steve