The original Lambretta handlebar gear selector only has the 4 gear positions for the original 4-speed gearbox. These gear changer housings no have precisely marked 5 gear positions to be used in conjunction with 5-speed gearboxes that are currently on the market. 
 
This one is suitable for Indian GP models only. These have the wider slot to take the handlebar bush, NOT the paddle type gear rod - please check before buying. 
 
PLEASE NOTE: these are NOT the CASA ones.