The image below was downloaded from Siegel's website, and is of lot 56 in sale 1247. Siegel states that it is a Scott #20 from Plate 4, and calls attention to the fact that top row of Plate 4 produced Type II stamps with the design complete at top. It looks to me, however, and almost without doubt, that there is a "secret dot" in the frame on the left. This would mean that it has be to be from either Plate 11 or Plate 12. The entire top rows of both of these plates also shows the complete design. The plumes at the bottom are less complete on Plate 12 than on Plate 11, and I believe that they closely match those of Lot 56. The guide dot, which is tangent to ornament "Z", appears to match best with 3L12.
The Scott value of a #20 from Plate 4 is four times that of a #20 from Plate 12, so it's an important distinction one has to make.