There are different opinions as to how to define Rock n Roll.  Many would think that the country, African cultural rhythms in blues, etc. description in the intro is appropriate.  I and many others would think not.  The intro is full of rockabilly and nothing to do with the funky rock n roll that expolded in the mid-50s with Little Richard, who Ray Charles, James Brown, Smokey Robinson and other rock n roll legends/pioneers considered to be the start of a new kind of music - funky, drivin, never let up rock n roll.  Bo Diddley also unleashed his own style of rnr in 1955. Berry was a combination of country and uptempo blues.  The three have been considered the Holy Trinity of Rock n Roll.  Nothing about in the opening?!  Unbelievable.