my 1950 5 window had wing window doors on it when I got it too, As stated above, it is very common to have changed doors over the years. Also stated above, a good indicator at this point for you (and me both) is that they do have the drivers side cowl vent right behind the fender. That indeed makes it older than a 1951. I am confident your truck is a 50 with 51 doors on it.
By the way....welcome
