How does a waterslide decal look on a metal coin door? You can also try: https://customrubontransfers.com
You can see what rub-on transfers look like on metal here -- see the shooter gauge in my post https://pinside.com/pinball/forum/topic/williams-1954-spitfire-restoration-complete
They are adhesive-backed screen printing ink, look like the original.
Getting a screen burned and screen printing it would be another way -- how it was done originally.