OK thanks. That certainly says 1971 but the cast and conductor are from
1967. The official Bayreuth website has a performance database - for
instance the 1971 Rheingold is here
You can see that the cast and conductor match the 1967 performances.
There's a discussion here about the misprinted date for the Rheingold and
Siegfried on a Decca set, which I suppose this must be from: