Although I cannot exactly date the poster stamps shown, this excerpt suggests that "The White Cross International Anti Narcotic Society" was in existence circa 1921-1945. An obscure reference suggests the poster stamps may have dated to 1932-1933.

The Children's Home Society of California dates all the way back to 1891 and it still exists today. It's history is documented at this link:
http://www.chs-ca.org/about-chs/our-history/Cal Farley's Boys' Ranch of Amarillo, Texas started in 1939 and still exists today (although it now is inclusive of both boys and girls) as shown at this link. The poster stamps most likely date back to the 1950s or early 1960s when using stamps as fund raising promotions were quite common:
https://www.calfarley.org/aboutus/history/