Possible Jack Benny cameo?

Is that Jack Benny in the Carnegie Hall scene? He's the timpanist who turns his head and gives the guy who blasts the steam whistle, the trademark Benny deadpan "look." Benny was known to do cameos in movies, and one involving music would have attracted him. This is at about 33 minutes into the film, on my laserdisc. It's obviously a carefully planned bit of business, meant to show a familiar Benny characteristic. That's what I think, but I've never seen it mentioned.

This is preceded by the gag in which Henry can't seem to wind up his cadenza in the right key, until the conductor mouths "B-flat."