Lot 253 Nigeria #16b 1d Deep Red & Rose Red 1914-1929 King George V Imperium Keyplate Issue, Usage On Two Postage Due Covers To The US

Two covers, both sent to the US at the 3d rate, but only franked with 2d in postage, with two die 2 red stamps each. On one cover the stamps are tied by July 10, 1928 Proud type D19 Calabar cancels, while the other has the stamps tied by September 4, 1931 Lagos cancel. There are no backstamps. There are different "T" postage due markings, but no postage due stamps.

Fine condition overall. The value of the cancels in Proud is nominal. The destination for the covers is not of any premium value, but the basic covers would be worth $5. The stamp value on cover is $3. The postage due markings should add $10. So, my estimate of the value of these is $18.