I don't know exactly when the change was done, but the overall shape of the door remained the same from 1947 to 1955. So mixes are possible.
What is sure, however, is that this pick-up has indeed the 1947-50 one-piece door windows, but also at least one 1952-55 door handle (with the opening knob), a 1953-54 hood side emblem and non-factory top-mounted wipers. And perhaps a 1947-48 cab, as the cab-mounted fuel filler pipe is missing.
Hard to give an exact model year, with all these incoherent details
(The hood emblem says 3100: that would make it a US model, as the Canadian version was the 1300)