This is a reproduction of the painting As I Opened Fire (1964)
in the collection of the Stedelijk Museum, Amsterdam. Over the years several sizable editions have been printed, and the reproductions are still available at the museum. A number of these reproductions have been autographed. These reproductions have often been mistaken for original prints.
Printed on each panel, lower right, within image: (© S.M.A.); printed on verso, lower left corner of each panel: (Roy Lichtenstein 1923 / as i opened fire / 1964 - acryl on canvas / triptych - panel (1,2, or 3) - 73 x 142½ cm./ coll. Stedelijk Museum Amsterdam).
This information is from The Prints of Roy Lichtenstein - A Cataloque Raisonne by Mary Lee Corlett, Page 292