Well, Nowhere Man, we considered Sunshine Superman psychedelic back in 1966. And we already had the term for it.
In late 1965 Grace Slick wrote this song and performed it with The Great Society...
The Great Society White Rabbit
We called that psychedelic too.
Maybe according to those early standards "Sunshine Superman" was considered psychedelic in 1966, but I think it wasn't in comparison to true psychedelic music that came later.
Thanks for that video of the Great Society. I'm a huge Jefferson Airplane fan. That early version of "White Rabbit" sounds rare, that's true, but I wouldn't call it psychedelic too, just my opinion. The definitive Jefferson Airplane version is certainly pure psychedelia, acid rock at its best (can't beat that Jack Casady's thunderous bass).