Yes, you will find photos showing different rear windows. However, if you don't also know the serial number, the photos alone will not determine if a particular car is considered early or late. I have photos of my Cord (2288H) taken ~ 1939, which show the small window and one piece top (without the removable back curtain). A friend owns 2300H which was has won primary and senior at Auburn. It is also considered early and has the small rear window. I don't know what serial number is considered the end of the early run, but I can find out if your interested.
There are other early