One thing I was surprised to see that was not on the recently released expanded edition of Mary's solo album was more unreleased leads she did while at Motown like the 1969 recordings she did. I thought maybe we'd get a cleaned up version of "Son Of A Preacher Man". Didn't she also record one or two other leads at that time as well? Were these just demos to see if Mary was capable of taking over the lead from Diana?
From what I remember they were recorded sometime in the spring of '69 which would make sense since that was when Berry started searching for Diana's replacement.