[a fool in paradise]

I think the original recording used a very low harmonica.

That would be my guess. The Beach Boys even used one on Pet Sounds around the same time (1967).

I Know There's An Answer

[cyclotic]

Some of the same session artists recorded both Green Acres and the Beach Boys.

Netflix has a really interesting documentary called “The Wrecking Crew.”

Brian Wilson was such a perfectionist that all the instrumentation on most of their albums was done by the Wrecking Crew, not the Beach Boys.