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. 
 
These suit the Italian TV and Li series 3 models: Li 125 & 150 (-'65), TV series 3 175-200 (-'65) , and Spanish Specials - These have the shallow slot to take the paddle type gear rod NOT the one with the plastic handlebar bush - please check yours before buying.
 
Please note: these are NOT the CASA ones.