During a show which takes place sometime before 1963, the Wilson brothers' mom takes pictures of them, using a 110-format Instamatic camera. The 110 film format was invented a few years later than 1963.
When Mike Love gets into his Duece Coupe after talking to his father you can see the ignition switch is on the steering column. Since this scene was right after Brian gave Surf City to Jan & Dean that makes it 1963. The ignition switch was mounted on the dash until the very late 60s.