1948-1950 side doors were the same. Slight differences in later years.
https://www.stovebolt.com/techtips/...ign/Advance%20Design%20Spotting%20Guide/

Here is a special-body (non-GM-made) crew-cab that used special-made rear doors:
http://1954advance-design.com/Web%20images/1954-Crew-Cab.jpg