Somebody knows... Maybe you?
Most of the pre 1937 pinballs used marbles and the machines were commonly called "Marble Games" back then. The only games I can think of that did use steel balls were the three in the Rockola mechanical series - 1933 World's Fair Jig-saw, 1934 World's Series and 1934 Army Navy. These all needed heavy balls of a small size to work the mechanical devices inside. Sometimes the non steel balls were made of ceramic like substances or bakelite/composition early plastics. Very hard to find matching sets inside a game after all this time. And sometimes the instruction cards will tell you there was a special coloured ball that scored double.
Usually just all one colour with possibly a high scoring ball different. The advert for Wings was wordy but no help about ball colours. Trying to find matching colour & size for any missing originals is almost impossible. I've collected some rare pre-war pins over the years and can't remember any of them being totally original with all matching balls. And often easy to spot the slight size difference so def not made that way. The marbles afford much better play on the early machines as considerably lighter than solid steel so livelier.