It would be a model 3608 (flatbed) or a 3609 (stake), but could also be a 3603 (chassis and cab) if the bed was installed aftermarket. Single wheels were std equipment on 3/4 tons, duals were optional, so it very well could be a correct 3/4 ton flatbed.
About the only things you'll get from the vin (door #) will be the assembly plant, year, series (series only, not body style), and month of manufacture.
