Only harmonics I saw/heard was early in the tune an artificial harmonic, and around 2:14 you see Arlen simply touching the fretted note 12 frets above for the harmonic. As to the end, Danny is using his pinky on the volume knob to make the sound swell, a trick a lot of Telly players use. Best I can tell after one look. Maybe cuz they're using Tellys using the bridge p/ups it only sounds like harmonics? I'm no sweeper, but I figure the only way you can sweep harmonics is if you had your guitar tuned differently; I'm reasonably sure they were in standard tuning.