Here is another resource for you.
http://www.deltateamdecals.com/ He makes a good product also. The best thing to do is do a google search for the army manual on marking of vehicles during the Korean War. A quick search pulled up this TB746-93-1 Color and Marking of Military Vehicles but it's a 1964 manual. Basically as you look facing the vehicle either front or back your bumper markings should be on the left hand side should be the higher unit 3rd Armor 1 Infantry etc. Then the next HQ (battalion generally). Then on the right side would be the unit marking usually the company this could be a letter like C company or a number like 531st and then the number the vehicle is in the order of march (it's place in the convoy). So the right side would be something like C-21 or 531- 3 and so on. Here is a fictitious unit and how the markings would look.
First Infantry Division, 53rd Military Police Battalion, Alpha Company, Truck 6 (in what I believe to be 1950's marking your mileage may vary)
1ID 53MP A-6
In a more modern approach it would look more like
1I 53P A 6
Now all you need to do if pick a unit down to the company level and your are all set. Also Armor used the Delta triangle and Battalion HQ used HQ on the right side and Headquarter company would use HHC.
I hope this helps. Good luck!