All old Vespa models have a running-in instruction on the inside of the frame. It specifies how the scooter should be ridden when new. Information on the mixture ratio, tire pressure or maximum running-in speeds in the individual gears are recorded here.
Some of these Stickers are also available as water decals. In this case, the Sticker is applied directly to the Paint - exactly as it was back then. Instructions can be found in the download area. Other versions are printed on transparent adhesive film, as is common today.
Conclusion: A nice icing on the cake, not just for oldies.