Bert Christman's last work on the strip was on 1938-06-xx, and Frank Robbins begins on 1939-05-22, with Howell Dodd handling the art chores during the intervening period. So, these reprints fall within that period.
Edmund Good was previously suggested as writer/artist, but his stint on the strip did not begin until 1944.
This strip ran between 1934-01-22 and 1938, so these reprints fall within that period.