Wert: Yes, you are correct in your above stamp observation.
Wet rotary press printing was used in the Arch/Leaf Issue from 1930 to 1932.
The SHEET stamp (A) [166, Die II] is wet rotary press printed (perforated 11.25 x 10.95).
The BOOKLET stamp (B) [166cs, Die I] is flat plate press dry printed (perforated 10.95 x 10.95).
I wish that Canada stamp catalogs would have this important basic stamp information.
This is found in the booklet on the following page:
www.stickneyrotarypress.com[The right side "P" in "POSTAGE" has a larger spot in it in Die II than in Die I.]
[For this stamp, Die I and Die II are found for both wet rotary press sheet stamps
(166b and 166) and for dry flat plate press booklet stamps (166cs and 166as).]