Dies are made by bending steel, called the knife, to the exact shape of the sticker. The knife is hammered into a board, and this assembly is what punches out the shape, on a variety of different machines. Google is your friend: “how to make die for die cutting”. Plenty of videos.
Remember, they didn’t need thousands of graphics all the time. Sometimes only one or two. Complex shapes were either cut by hand or machine. Capsule stickers, yes, they used them all over. Single use graphics were probably done the cheapest way possible. There is a sign shop on the Paramount lot where all the vinyls and silkscreened panels came from. I’m sure their technology changed over the years, from manual punching to laser cutting & so forth.