The 1st printing is characterized by a ragged irregularity in the lower right corner on the inside edge of the 1/16" wide blue border. The remainder of the blue border is not perfectly straight, but lacks this rough, "saw tooth" quality. This original printing pre-dates the concert and measures 13 15/16" x 24 5/8".
The post-concert 2nd printing lacks the above-described rough area; the blue border is smooth and even. The orange is a bit more red than in the original. About half of these 2nd printings, 2nd Printing A, have three small white dots in the blue triangle in the upper left corner of the poster. It measures 13 13/16" x 24 5/8"
2nd Printing B lacks these white dots and also measures 13 13/16" x 24 5/8".
The 3rd printing incorrectly adds "26" after the "Wes Wilson '66" credit, and the blue ink on this printing is much lighter in color. This post-concert printing measures 13 7/8" x 24 9/16".