I think the notion that Heroes were 1920's marbles is a mistaken theory. It is one of the things which has or should have fallen by the wayside as we have learned more in the past couple of decades.
The first appearance I can recall of the Hero and Unique names in advertising dates to the 1950's with Master's purchase of the Akro assets.
And the patch marbles that we think of as Heroes and Uniques do not match Akro's inventory from the 1920's.
Akro's earliest patches that I know of from the advertising were the 1930's patches: Moss Agates, Royals, Tri-Color Agates.