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

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

2nd LT INF on November 25, 1940

1st LT INF on April 2, 1941

CAPT on September 19, 1942