This Format was published between 1902-1923. Today I am adding a picture of a dust jacket for title #32.
These books can be dated easily by reviewing the ads in the back of the book. There is a flow chart on the site to help with dating, see: http://henryaltemus.com/series/series202F3.htm
In this book Grunty Grunts is noted in the Wee Books for Wee Folks List. Thus, the publication date is 1922.