Lotsa kinds of music went into Rock 'n' Roll. Western Swing, Boogie Woogie, Bluegrass, Rhythm 'n' Blues, Blues, and yes, Country.

I have a few cuts of guitar great Charlie Gracie doing Boogie Woogie in 1951.

Bill Haley did Western Swing from about 1948-1952, but did some Boogie Woogie stuff too.

Carl Perkins did tough club dates playing an electric guitar and doing dance music between 1951 and 1954. Even did "Rose of Old Kentucky" as a dance number before Elvis did.

The Post War period from 1945-54 is a real mystery to most folks, at least it is now.