Hi Aussie.
In my opinion, the "type" (conformation) of the dogs has not changed, in the sense of the dogs of the past and the field-bred Labs of today. They look nothing like the show-bred Labs of today, just as field-bred Labs don't. If anything the Labs of the fifties and sixties might average an inch or two taller than the average Lab of today. (There are too few of the other retriever breeds on the films to draw any conclusions.)
The desire, intelligence, trainability, etc. of the dogs, again, seems identical to today! Nothing about the dogs has changed. They were stylish and loving every minute of it.
The National Am and National Open tests on the films appear very much like a Seasoned-level test from HRC, more than anything from AKC. They do not look like modern field trials, they look like modern HRC hunt tests. The distances are shorter, they have walk-ups where the handler live-fires the gun (in one he even shoots the live flyer).
The dogs are obviously not collar-trained as they grow "independent and rangy" the further they get from the handler, ignoring whistles. We hadn't learned how to effectively "reach out and correct them" yet.
In sum, the dogs have not changed, but the game has changed tremendously as has the handling. The handling is cleaner and more "professional."
But the game and the handling had to evolve, because we still have not found that bar the dogs cannot hurdle. We keep pushing them to learn more and more, harder and harder concepts, we piggyback the concepts, it doesn't matter. As long as we are fair to them in their testing, they learn everything we throw at them, and they do it with style.
Shortly all three films will be available to the retriever community.