Frank, you're spreading a myth - all vehicles have always had a Vehicle Identification Number, just not the elaborate things they have now, and if any DMV person is stupid enuff to dispute your VIN because it isn't 35 characters long, they should be laughed at and educated, not bowed down to
the VIN on our old trucks consists of information that identifies the year, model, and production sequence #, [which is the actual 'serial number'], and so are unique to the vehicle - it will be found on your title listed as the VIN, not the 'serial number'
that won't help you at the DMV, Magilla - only thing you can do is find a number on the vehicle that matches the one on the title - if you don't have a title you're in a whole different ball game
Bill