For the 1938-46 KGVI pictorials, Steiner has 2 spaces for the 2½p issue. The other major cat numbers match.
Steiner does not mention in the box of any differences like color as usually done.
Going to Scott, the 2½p is 87 and there is a minor variety in 87b (blue & black). What is not consistent is that there similar minor varieties for the 1p's, 2p, and 6p but no spaces.
