This stamp is only found as type A, on paper CL2A. I do not find it as an official. These have a horizontal-running watermark.
The following strip has an unusually clear impresion.
This pair has a peculiar shade and comes from a relatively clear printing.
This is the most common shade for the horizontal watermark stamps, and shows the typical significant plate wear found for this printing.
This is an exotic color, brown black.