Newly discovered Jimmy Blanton photos

In September 2007 Fred Reif sent me these photos. He had obtained them from the original photographer (now deceased) with the note that they were taken at the Michigan State Fair, probably in 1941.

I threw this out to some jazz scholars who wrestled with the problem: Cootie Williams left the band in November 1940.The Ellington band was in California in 1941 with Jump For Joy. Using the tracking skills of several Ellington experts, we came up with the possibility of MSF in late August of1940. Would anyone like to opine on this?