Well, no, not exactly. It turned out to be a Donovan song which was familiar anyway! "Sunshine Superman." I just had never put the two together. But that's where the beat came from.
FYI. The jury is still out over whether Imani Coppola ripped off Beck with that beat, since after all, according to WhoSampled.com, Beck sampled the beat in "The New Pollution" from yet another song, "Hallelujah Alright Amen" by Gus Poole.