This microphone was, in all probability, a model DN made by Astatic, which they called the "Commentator".  Stromberg-Carlson was a major manufacturer of public address equipment in the 1940's and 1950's, so it would appear that they just put their own name on microphones they bought from outside suppliers.

The vertical bar on the stand was an actuator for the "grip-to-talk" feature.  This microphone and matching stand cost about $40.00 in the late 1950's.