Determine model from serial number

[delta31]

We have a long wheel base truck without the rear body. The model number on the glove box data plate reads M37 so we suspect that either the glove box door or the body or both were not originally with this frame.
The configuration of the body mount bracket leads me to this this was originally and ambulance. If appears that the fire depart had removed one of the body mounts so I am not sure what the nomenclature/model.

We have the serial number of the left front side of the frame which indicated a manufacture dated of 1953. How can I cross reference the serial number to the model number? I came a cross a dodge website where I entered the serial number and that came back as M37. At the wheel base is 126 inches, I am guessing that this was an ambulance. Appreciate and suggestions. Thanks