Goldfinger was on again tonight, so taped that segment and on a larger screen & paused at the right point - you can very briefly see the join when they've put an extension over the reduced front section of what does now look to be a Webley.
(So much for believing the Internet Movie Firearms Database)....
Well spotted Lakey...
An early Tempest design ? LOL
Airguns in movies.
http://www.imfdb.org/wiki/Air_Guns