Lot
55 P
1851, 6d Black, Plate Proof on Card, Overprinted "SPECIMEN.", block of nine with diagonal "Specimen." overprint, rows 3/5, margins all around, Very Fine and choice, ex-Koh. SG No. 5 var. Scott No. 4TC4S Estimate $3,000 - 4,000.
A RARE 1851 6D BLACK PLATE PROOF "SPECIMEN" BLOCK OF NINE.
There are only one other block of four and a block of 16 known with the "Specimen." overprint.
Realized: $2,400