The postcard was printed before the concert. Each variant measures 4 1/4" x 7 1/4".
1st printing A has a "Place Stamp Here" square in the upper right hand corner of the reverse.
1st printing B has a bulk rate permit #642 imprint on the reverse.
1st printing C has a bulk rate permit #642 on the reverse and were mechanically addressed and sent to people on the mailing list.