There should be a metal tag on the bottom. You can check the number here on this site Radio Reference Guide There are two different models for the AD trucks. They look very similar and both fit from 47 to 53. Here is a photo of one Radio Photo


1951 GMC 1 Ton Flatbed -- It is finally on the road and what a great time I have driving it!
1951 1 Ton Completed


My Chevy Master 4 Door is on the Road!