Ken:
I think you're joking, but just in case:
Actors usually have no idea what goes into the sets they're acting on - it's just not their job. They usually see sets for the first time on the day they're shooting on them, or perhaps a day or two before. Their acting skill, and a little rehearsal, is what makes them look like they've lived on the set forever.
I do hopefully have a trip coming up to the Academy to research some issues with The Birds, as well as another Hitchcock movie, and perhaps there's an answer there. But it's going to be something in the set drawings, or some correspondence between Hitchcock and Robert Boyle, who designed the sets, or George Milo, who was the "set decorator," meaning the person who chose the furnishings, decorative objects, etc.
Hopefully, someone left a memo or other indication about this, because all of these men are, as they say, No Longer With Us.