I really don't know how I missed that card- I search for Standard Biscuit and 1921 on almost a daily basis, and occasionally for Thomas himself.
Rhett, note that the typeset is different on the C in Cleveland than it is for the E-121 card of Pinch:
then note how the C in Cleveland is the same for his Henry A. Johnson card:
Does this tell us that the Henry Johnson type w-575's came out with Standard Biscuit and before E-121?