On the dark side

This song is "On the DArk Side," from the movie Eddie and the Cruisers, done by the band John Cafferty and the Beaver Brown Band. I haven't seen the movie in ages, but I hear the song every now and again on the radio. Every time I hear it (just tonight on the drive back from the gym), something bothers me; this song is supposed to be written in 1963. Hmmmm. To me, there's no way this song comes from the early 60s; doesn't sound like anything from that period, IMHO.