Label makes no differentiation on artists. Some tracks could be just Dave, some could be just Jerry's, some tracks could be both. There is organ on all tracks.
Some sources indicate 1966, but Crown records discographies at both "Forbidden eye" and "Both Sides Now" indicate 1963
The artist on each track could be anybody.
The Happy Organ" at an uncritical listening does sound like the original but one would have to compare side by side.
Crown had a very cavalier attitude towards what they put on the label for the artist's name.