|Here are two slightly different Royal Enfield headbadges from the 1950s. The left one is made from brass, the right from an unknown alloy with a gilt finish.
The alloy one came on a 1955 Royal Enfield Superlight, (531 frame with REs own alloy chain-wheel and brake calipers, now quite rare.) The brass one was an ebay find and predates 1955. Not sure exactly when they changed over but were in use post 1945. I think the Redditch stamped version was pre 1939.