Wanted information on 1903 Cadillac and 1903 Ford Bodies

Does anyone have any information on how similar the 1903 Cadillac body and 1903 Ford bodies are? In one of the 1950s HCCA magazines there was a note under one of the pictures that mentioned that the same body builder supplied bodies to both Ford and Cadillac. I know the Ford body supplier was C.R. Wilson Carriage Company. They obviously look very similar, but I would like to know if they are like the modern day Dodge Caravan and Chrysler Town and Country -- same dimensions and many parts would interchange or if they looked similar but nothing would interchange. Thanks for any help or leads you can offer.

Hap Tucker 1915 Ford Touring cut off and made into a pickup truck and 1907 Model S Runabout