I have a gold color 1992 US Penny that sticks to a magnet. I also have a 1943 Steel penny and a 1943 silver colored penny that sticks to a magnet.
They are made of steel. Steel sticks to magnets. In 1943 Steel was used instead of Copper. Copper was used instead for the war effort. You know, bullets
Plated with nickel and then gold plated. The nickel plating is done because the subsequent gold plating will adhere to it better.
Looks like that or either nickel plated and then heated for bronze to form, nickel is ferro-magnetic.