Hi manXcat,
The A7 barre chord I'm playing during the Intro and Chorus of "She Loves You" (at 1:04 on Chorus video) is the the full six-string barre at the 5th fret with the pinkie on the 2nd string/8th fret. There's many ways to play a given chord on the guitar and a chord finder/dictionary might not contain every variation as in this case. Playing this A7 barre chord without the pinkie is fine as well and I don't think anyone listening will know the difference. My ear tells me the Beatles are voicing the chord as I taught in the lesson, but either way will work.
I hope this clears it up!
-Dave