This is an interesting car. Unfortunately, two items were missing from the photo parade that would be VERY significant to the vehicle.
Photos and information from various 1947 and 1948 issues of KAISER-FRAZER DEALER NEWS confirm that a number of Kaisers and Frazers were turned into taxicabs The body number suggests that the body was built in July of 1947 but shows nothing to indicate a modification. Odds are that if the Taxi company existed in the Chicago area back then, this was one of the vehicles with one interesting exception.
The ad stated "vinyl upholstery" but there are no pictures of the interior. If there were, it could be determined if this was done after the car was built or was the same material/pattern as used on a 1948 Frazer Taxi prototype that I mentioned in the Spring 2019 issue of the QUARTERLY in the article GHOST CARS. This may not be the same interior set up as the prototype...no way to know.