The box looks fake. There is a certain Welsh gentleman who knocks them out.
Lawrie showed me one and the writing was mirror-reversed!
The interior looks genuine enough. Though at that price even if a fake box cost you £300, you'd make your money back.
Vintage Airguns Gallery
..Above link posted with permission from Gareth W-B In British slang an anorak is a person who has a very strong interest in niche subjects.