A scene dated March 1961 has George being wished a happy 18th birthday. George's actual birthday was in February (as was even mentioned earlier in the film.)
At the end of the film, text describing subsequent events is superimposed over shots of a beach. One paragraph notes that Klaus Voormann played bass on John Lennon's album "Imagine" and designed the Beatles' "Revolver" album cover, but although the former title is placed in quotation marks, the latter is not.
The train carriage at Hamburg station has a date of 22.2.90 stenciled at the bottom. This will be the date of the last full service, 3 years before filming but 30 years after the action.
There are at least one movie posters visible, that aren't from that period. "Svezia, inferno e paradiso" (aka Sweden: Heaven and Hell) movie released in 1968, and it can seen in movie theatre scene (At 01:05).