@old_mopar_guy is on the nose. Once cars got to be more common - late 1900’s - it was common to buy the car as a powered chassis without the body. The car would be delivered to the “coach builder” and a wood frame would be constructed and the metal (or fabric or wood) body would be built onto the wood frame and then installed onto the chassis. The bodies often cost as much as the chassis themselves. Very well heeled owners could have both an open top coach built for the summer and a closed top car built for the winter. The bodies would be swapped seasonally much like winter and summer tires!
Coach builders like Fisher, LeBaron, Dietrich, James Young, or Figoni and Falaschi would build bodies for multiple car manufactures. Fisher built bodies for Cadillac, Buick, or Studebaker, LeBaron built for Duesenburg, Rolls Royce, Hispano Suiza, Packard and more. Dietrich, an original LeBaron founder built for Packard, Franklin and Studebaker. James Young bodied Bentley, Rolls Royce, Singer, Sunbeam and even Alfa Romeo. Figoni and Falaschi designed some of the most beautiful cars I’ve ever seen for Delahaye and Alfa Romeo. See below for one example built for Delahaye.
