This is how the dealers I worked at handled paperwork for new cars
When the car(s) arrived at the dealer,a person (usually a sales person) was assigned to ?check in? the new cars. This was a very important process to keep records accurate. Each car came with a large brown paper envelope that held copies of window sticker,owner?s manual,as well as any optional equipment tags,which varied by car. Also included were both sets of keys. Small tag provided the key codes ,A #was ignition and B# was trunk. It was the person that checked in each car that was responsible for inspection for damage,or missing items. Those envelopes were then processed to inventory into dealers system. It was then that key codes were noted and recorded on the invoice copies. The duplicate keys stayed in envelope,the main keys got the common key tag with description and stock number and stored on keyboard in secure location.In my pictures you can see the two codes A and B and four digit code. The four digit code could be used to convert to five digit key cuts. Those envelopes were filed in filing cabinets by stock number assigned. If everyone did their job correctly it worked fine.