I have seen a site that decoded all 'VIN' numbers. However, the context of that site was the uniform Vehicle Identification Number that was implemented some time back, maybe the 80's, but which does not include the trucks we care about here.
VIN and Serial Number are often used interchangably, but there does appear to be some difference in what they mean.
I've been collecting information with the intention of creating a web page that will intrepret a serial number and tell what it means. I'm starting with '47 - '55 1st Chevrolet and GMC Trucks only, but will expand as I gain command of the process and more information about what the numbers and letters mean.