WWII Homefront "V" Victory Keys were produced during the war years in two sections, as is aparant from the diagram and photos. This was done to help conserve brass, which was in short demand; the upper section is brass and the lower section was in steel. These were produced for both home use and for automobile keys. I can recall these from when I was a young lad during the wartime period.
The first photo is of key blanks that were for manufacture of home keys showing both sides - Second photo is a closeup - third photo is of ones produced for automobile keys showing both sides (blanks for Chrysler Dodge Plymouth Desoto 1943 to 1948) - last photo is of the diagram showing the construction of the keys. I'm not certain as to what the numbers in the diagram indicate.