Below are some approximate production dates that will help you date your Webley Air Pistol. And currently produce a fine range of air rifles and air pistols that are available worldwide.
Webley experimented with pneumatic air rifles in the 1960’s.
I think they have since dropped NEF as it was redundant. From the company's website: Freedom Group is the world’s leading innovator, designer, manufacturer, and marketer of firearms, ammunition, and related products for the hunting, shooting sports, law enforcement, and military markets.
As one of the largest manufacturers in the world of firearms and ammunition, we have some of the most globally recognized brands including Remington, Marlin, Harrington & Richardson, New England Firearms, L. Smith, Parker, Bushmaster, DPMS/Panther Arms, Dakota Arms, EOTAC, and INTC. Can we assume this information applies to their products across the spectrum of what they offered for sale?
Later Pistols were the marked with usually a threedigit batch number.