Wait I haven't really seen the movie in a long time but the plan was to not steal anything in Fort Knox? Just let people think they did to devalue gold? Weren't they loading it up though on trucks?
Also, the Fort Knox scene is highly unrealistic considering there is a base there (Fort Knox) with plenty of troops and tanks (I've actually been there) within a short distance of the vault. Basically, it is almost impossible to break in considering there are army troops stationed right there. If anything they could overpower the guards but then get run over by troops and tanks within a few minutes.
One more thing... Netflix has pretty much all the old Bond movies on instant stream for anyone that didn't know.