PAPUA. 1930. INVERTED OVERPRINT, AIRMAIL PLANE. REPRO.  Only 1 sheet of 40 printed.  It is not known how many of this overprint still exsist.  SG list this stamp as SG 117a. 1 mint stamp sold at auction in 2018 for A$26000.00. Value estimate 2019 Sterling$15000.00. [A$29000.00]. MINT. Per stamp. Sterling$30000.00 [A$58000.00]. MUH. Per stamp.