The exact location of a Vespa number will vary depending on the model of your scooter. However, it is usually located somewhere on or near the engine.
On the frame
The frame
Frame
On the frame
Look on the frame.
look on the frame
Check the butt or frame.
On the frame. It's on the steering tube
On the frame
Frame and/or butt
Serial number is on the frame.
mine was on the front of front motor mount