Greatest Hits Volume 1 is a greatest hits compilation album by The Beatles which was exclusive to Australia and New Zealand. The album was compiled by EMI Australia to fill in the gap between "Rubber Soul" and "Revolver" (much like "A Collection of Beatles Oldies" would in 1966 in between "Revolver" and "Sgt. Pepper's Lonely Hearts Club Band").
Sgt Pepper's Lonely Hearts Club Band was released after 1966
If Revolver and the Greatest Hits albums were released in 1966, and they only released the Greatest Hits to bridge the gap between the albums, it can be concluded that Sgt Pepper's Lonely Hearts Club Band was released after 1966.