"Baby You're a Rich Man"

I listened to Magical Mystery Tour this morning, and the line "Tuned to a natural E" in "Baby You're a Rich Man" caught my attention.  I'd wondered whether the vocal line there is actually singing "E" to an E note, but I'd never actually lookt into it.  I finally did, and I discovered that neither the lead vocal nor the harmony vocal sing an E note there.  The lead vocal sings a G, and the harmony vocal sings a C.  For what it's worth: adding an E would result in a C major chord, and the song is in C major.