How to verify builder of 1941 Hudson Station Wagon.

My friend Robert Blake owns a 1941 Hudson Super Six Station wagon.  We are attempting to verify if it was built by Cantrell.  We could not locate a tag in the car to confirm this fact.  Where would the tag/badge be located?  I have researched two books to gather information.  The Don Butler Hudson book indicates 1941 Station wagons (all) were bodied by Cantrell.  The second book I reviewed was by Richard Bhoechl titled "Woodies & Wagons".  That book states all 1941 Hudson wagons were built by Mid-State Body (located in Waterloo, NY).  Obviously there is a discrepancy.  Also, would there be a particular spot on the car (other than the missing name plate) that can verify the builder of the wood body, perhaps a stamped ID number.  Any guidance would be appreciated.  Thanks to all and have a good day!
Rose Miller