Yes, it was "motor-vatin'."

Until I saw this thread, I had no inkling that there ever were "original" lyrics to Maybellene before Chuck Berry. I accepted it as a song he wrote. I could see that it might have been inspired by Ida Red, though "reworking" strikes me as a reach.

If you will indulge me, what is the basis for believing that there was some form of Maybellene prior to Chuck Berry's release of the song?