Back before stainless steel was in common use, brass was the go-to metal for things like that, because it was very easy to form, didn't rust, and could be chrome plated without a lot of intermediate steps that steel required. In the WWII years, brass and copper were reserved for production of ammunition, and so more things got made out of stainless steel. Remember the steel pennies from 1943? Brass was in such high demand for the war effort, that even cartridge cases got made out of steel. Even in the Korean War years, Chrome was a war effort reserved metal and the '53 Chevy pickups came with painted bumpers instead of chromed ones.
