Throughout the movie, Jimmy Page and John Paul Jones have different outfits on. However, this is because the movie was filmed when the band played Madison Square Garden 3 nights in a row in 1973, and both Jimmy and John Paul didn't want to wear the same outfits. Small portions of songs were also filmed in 1974 at Shepperton Studios because of missing pieces of songs.
Near the end of "Dazed and Confused", during the camera-spin, Jimmy Page can be heard soloing wildly in high-note arpeggios for which his fingers should be closer-to-the-body (his AND the guitar) but the footage shows clearly his left hand up closer to the headstock in chord-strumming positions. During the same song there are obvious footage inserts where he is not as sweaty as he appears in clips preceding, following, & throughout the rest of the song.
Right at the end of Whole Lotta Love, there is a camera shot from above the band, over the stage looking down. John Paul Jones can be seen removing his bass guitar and putting it on a horizontal surface. Then the camera cuts to a front shot, as seen from the audience and Jones still has his bass guitar around his neck.
In the sequence where Peter Grant, the band's manager, is pretending to be a 30s gangster, two different vintage cars are used in the same sequence. This is most visible by looking at the hood ornaments.
When the band is playing Whole Lotta Love, when Jimmy Page finishes the solo and starts on the main riff again, he has the red Led Paul, but when the camera changes angles he is playing the Sunburst model.
Prior to the montage in Whole Lotta Love you see Jimmy Page playing the Sunburst Les Paul. Moments later you see him walk to the right of the screen with the red one and exchange it for the Sunburst model (which he was already playing).