I recently received a scan of a page from an archive of National Guard records and it lists all of the dates where my father received rank.
Here are the dates and ranks:
Illinois National Guard Rank
Illinois National Guard Rank
From PVT to PFC INF on October 17, 1933 until April 24, 1935
From PFC to SGT ENGRS on May 7, 1935 until May 30, 1938
From SGT ENGRS to SGT INF on November 2, 1938 until November 19, 1940
Promoted to 2nd LT INF on November 23, 1940
Federal (US Army) Promotions
Federal (US Army) Promotions
2nd LT INF on November 25, 1940
1st LT INF on April 2, 1941
CAPT on September 19, 1942