you might be right, if you believe this letter from "Michigan Today":
I originated the cheer during Michigan's 1947 baseball season.
At that time, M-Club members would sit together at various athletic events to support the members of other varsity teams. We even had a special M-Club section at the basketball games, then played in Yost Field House. Members of the athletic teams were quite supportive of all of the other teams during the 1946-51 period.
During the 1947 baseball season, I began cheering, "Go Blue" and "Let's Go Blue" as an alternative to the lengthier cheers, such as "locomotives" in use at the time. The brief "Go Blue" and "Let's Go Blue" could be cheered while batters came to the plate without disrupting the flow of the game.
Other members of our M-Club section picked up the cheers, and we had quite a loud, supportive group. Next fall, I continued the cheer in support of the 1947 National Champion football team. And during the 1947-48 basketball season, our M-Club cheering section rooted the team to Michigan's first Big 10 basketball championship in many years with lots of "Let's Go Blue's."
After graduating in 1951, I was away from Michigan for several years. When I returned for a football game in the early 1960s, I was astounded to hear thousands of Michigan fans chanting, "Let's Go Blue." I have been a football season ticket holder since 1965, and during that time I have felt a sense o pride each time I've heard the Michigan fans cheer the "Let's Go Blue" I first cheered in the Spring of 1947.
Charles J. Moss '51
Midland, Michigan