Not in Durland; no Scott Number assigned. Corresponds to Scott J31. The plate is listed in Cleland as "not hardened or used, proof exists". There is a smear of red ink on each of the four corner stamps of the proof sheet.
Certified plate proofs are the last printed proof of the plate before printing the stamps at the Bureau of Engraving and Printing. These plate proofs are each unique, with the approval signatures and date. For postal scholars these plates provide important production information in the plate margin inscriptions, including guidelines, plate numbers, and initials of the siderographer, or person who created the plate from a transfer roll.
