Ritchie Valens' "Now You're Gone"

A few days ago, I listened to a compilation album of Ritchie Valens.  I really like his "Now You're Gone," so I decided to learn how to play it.  I think I figured it out one other time (or at least figured out most of it) because I sort of remembered it.

In any case, I learned some cool things about it.  First, it starts off with a key change... sort of.  It starts in C# minor (for three chords) but then changes key to E major.  They contain all the same notes though, so I'm not sure if it's technically a key change.

Second, while it is mostly a three-chord song, it has E major 6ths, which I don't think is something that's all too common in 1950s songs.

EDIT: I'd been playing this with a capo on the 2nd fret, so all of the chords I said are relative to the capo.  It actually starts in D# minor and changes key to F# major.  And it contains an F# major 6th.  So even aside from the sudden key change and major 6th chords, there's something else distinctive about it - it's in an unusual key compared to most 1950s songs.