Pre-Fab Four??
The comment in the plot outline is erroneous in two ways. Firstly the Monkees were obviously *after* the Beatles so, if anything, they would be the 'Post'-Fab Four amd the wordplay fails and, secondly, the name 'Pre-Fab Four' had already been used and assigned to the Rutles in the films/mockumentaries. The phrase 'prefab' refers to the British practice of erecting cheap 'prefabricated' housing post-WWII, or as it is now known in the US as 'manufactured housing', and as the phrase is British should not be allocated to an American band.
Just my two cents<del><del><del><del><del>pence...