Summorum Pontificum and Sacramentals

A question was brought to me last evening that I couldn't answer: Does Summorum Pontificum give priests the right to use versions of the sacramentals that pre-date the liturgical changes? For instance, would a priest be required to use the current Book of Blessings, or could he revert to an earlier version?

Has the priest always had this freedom, even pre-SP?

If you're qualified to answer this question definitively, please do so in the combox.