Bette Davis movie "Dead Ringer"--Band in nightclub

Factual Questions
1

In this movie, made in 1964, Davis plays two twin sisters, one of whom runs a bar. Through most of the bar scenes a bluesy instrumental band is heard which sounds an awful lot like Booker T. & the M.G.'s. However, they’re not credited, and I couldn’t find anything about this possibility either in http://www.allmusic.com or http://www.allmovie.com.

Does anyone know the truth of this?

2

According to http://www.imdb.com, Andre’ Previn is credited with the music, so he could have written the music for the band… But I don’t know, haven’t yet seen the film. Maybe Eve has, if she shows up here…