Some time back, I reported what I now believe to be an error regarding the set Dennis Wilson was playing in the Lost Concert from 1964.
I had indicated that you Gretsch guys should check out the Swivomatic mounts on his Gretsch set. But I was wrong. That is a Rogers set with B&B, and I even think I want to place a second view of the sizes as being 20,12,14,14 with the 13 Gretsch added to the right-hand side by means I can't determine from the video.
But the 12 is clearly on a single Swivomatic mount. Earlier I had speculated all Gretsch with a 20,12,13,16,16 layout. But we know that with time he was moving to the 20,12,14 configuration seen with his Camcos that did have swivomatic and knobby hardware.
My guess is that he added the 13 Gretsch tom from an earlier kit he had that is definitely a Gretsch Bop kit of 20,13,16 variety. Those were very popular at the time. In the Surfin' Safari vid on Youtube, you can see the set and the band doing the lip sync thing that was so common to television at that time.
This is when David Marks was first in the group and the vid features him playing the nice guitar solo/lick rather than Carl. Funny too that Mike, who is usually so confident, looks a bit shell shocked. But they were all obviously very young at that juncture.