AAMS CL30c $440.00
CL30c inverted overprint variety on May 2, 1928 cover from Rolling Portage to Red Lake. Red Lake May 2 back stamp plus a Western Canada Airways Limited May 2 1928 Red Lake Ony. 4 line hand stamp. Unitrade footnote states stamps with inverted overprints are worth $200.00 each. Scarce on cover.