This bike was located in England so I began the exciting task of dealing with the DVLC (our equivalent of the DMV). License plates in England are issued to a vehicle when it is bought and a letter in the license number denotes the age of the vehicle. A bike like this will have much more value if you can get an original plate but this is a real pain to do.
You have to verify the age of the bike with a letter from a respected authority (The Lambretta Preservation Society), have the bike inspected by a mechanic, provide proof of insurance, and pay through the nose to get it registered.
Each year when you register the bike it has to go through a full inspection where the usability of the brakes, functioning of the horn, lights, muffler, and any rust issues are all checked for compliance. Even tire wear is noted!
The DVLC must be notified if you make any changes to the bike (although many people change the motor from a learner legal 125 to a 200) including the paint color of the bike.