Although a very few prototypes had been built between 1965 and 1967, and about six pre-production models early in 1968, 'Lightweight' Series IIA quantity production began on 11 November 1968, with a total of 15 vehicles being produced on that day.
The Series IIA Lightweight was replaced by the Series III Lightweight in 1972, soon after the replacement of the civilian Series IIA with the Series III.