The ownership of sheet music does not allow one to perform the music publicly without a performance license.  The rights are seperate rights, and if performing music publicly, it is proper to have a performance license.  The phrase "All Rights Reserved", that is generally printed at the bottom of the copyright music on stock sheet music means that all rights that relate to the copyrighted composition contained in the sheet music musit be licensed.  These rights could include Grand Rights, Synchronization Rights, Mechanical Rights, and Performance Rights.  To learn more about performance rights, click here.