I apologize for my error. It's a bit of info passed on to me at some time in the past. I was told it was to easier facilitate the extraction of an injured person from the cab, where access wasn't possible otherwise. Probably the reason for my thought that it was something mandated by a "higher" authority. Although I must say, I have never seen a "light" truck later than '67 with a small back window,(not even a Dodge)I'll take your word that they do exist.
