In Malehorn and Davenport's "United States Sales Tax Tokens and Stamps: A History and Catalog, this token is identified as AZ-S6. It has an R-1 (very common) rarity rating.
There are 3 minor strike varieties:
AZ-S6a - There are thick letters and a rounded numeral on the reverse.
AZ-S6b - There is a partially rounded, partially flat numeral on the reverse.
AZ-S6c - There are thin letters and a flat numeral on the reverse.
I think Schimmel's made an error on years of issue. Schimmel indicates next to the photos that years of issue for that design were 1937-1945, then does not indicate and years of issue for the copper variety and shows 1946-48 for the brass variety.

Not sure how that can be.
Malehorn and Davenport list the copper version as being struck from 1937-1942. Your brass variety is listed as being struck in 1945-1946 at a mintage of 550,000, and these tokens were made by the Osborne Register Company. They also note that Gordon Jones of Phoenix, Arizona bought a hoard of 200,000 AZ tokens when the state discontinued use of them, so additional varieties may be waiting to be discovered.