The 2pCL1B of 1943 is the scarcest stamp of the entire issue. I just came across this stamp. Several features of this stamp are give-aways: the stamp is postmarked 1944 (and 1943/44 are the correct years only), the paper is bright white, the watermark is perpendicular, and the ink shows some splatter.
Here is a comparison 1E1/3.
The watermark is barely visible, as it should be. The RA is perpendicular to the 1E1/1E3, as it should be.
Here is a detail showing how the ink tends to splatter on the clay coating.
These details show differences between the clay printing (top) and printing on the 1E1/1E3 papers (bottom).