That type of VIN is really just a model+serial number. It doesn't describe any of the features of the truck like newer VIN's do. You have to use the plate under the hood to determine engine, trans, axle, etc.
That's not true, sure you don't get as much info on earlier VIN's but there is some info there like where it was made and if it were a special edition vehicle but that's about all you can get from them. Even some late model VIN's can be vague though, as an example there is no digit on the Buick Regals to denote which one is a GNX (Grand National) and which one is just a plain Regal. Kinda sucks in determining if it is a fake or not, but it does hide what it is from your insurance.
