There are just so many movies that use whatever the prop department has available, regardless if it was even invented yet.
There was a scene in Casablanca where Bogey is talking about some guns he used, but the defense department didn't want he Germans to know about these guns, so they were changed to something else.
And, speaking of Casablanca, there were many 'goofs' making this movie, bottles that were filled were suddenly half empty, only to be full again in another shot, cigarettes that were lit, then out, then lit again, drinking glasses on one side, then another and the list could go on.
In the opening scenes of Casablanca, we see the busy streets of this city, with shops and such and then we see Rick's Cafe amid these shops. But later in the movie something happened to this--????
When Rick and Elsa were in Paris and Rick was supposed to meet her at the train station, he and Sam waited in a pouring rain. When Rick reads the note from Elsa, the note dissolved from the rain, yet when we next see Rick at the train doorway, he is as dry as a bone. Movie magic???
Now, watch this clip and see what 'goofs' can be seen.