jjarmstrong47 - You've got it! Thank you for pointing out the S clearly to all
of us.
lithograving - I am afraid that everything I can do to be helpful is comment.
As for Czechoslovakia Scott # 222, as I said there is
no engraved initial. What some collectors perceive to be suggestive
of a white S is one
of the white S-formations appearing in the engraving
of the rock, either yours or another one as published in the philatelic press in my country, located just above the right-hand value tablet opposite the very top
of the digit 3. Above the frame
of the value tablet, you can see two engraved lines shaping the rock and just above them appears a white S to some observers.
See enlarged detail
of Sc. 222 in
https://goscf.com/t/9106&whichpage=227#526393Also note ink bleeding, as pointed out by
jjarmstrong47, while examining the enlarged detail, e.g. in the frame
of the value tablet, this effect being due to Stickney rotary presses printing on "wet" paper.