So called because of it’s resemblance to an old clothes iron. This has five stages of wear & tear in the film:
1. Undamaged: Best seen during the USO shows and the serial. No weathering or wear. It’s possible the serial shield is painted with black rather than blue.
2. Light Wear: Best seen when Rogers sneaks into the Hydra factory for the POW rescue, especially when he bonks the guard before exiting the truck. This lasts through the POW release.
3. Medium Wear with No Punch: There is a bullet hole below the right star that must have been acquired after freeing the POWs but before finding Bucky. This bullet hole appears to go all the way through (at least one of) the shield(s).
4.Medium Wear with Punch: During and through the fight with the Red Skull.
5. Heavy Wear with Punch: Seen only after the escape from the Hydra factory. Soon replaced by the circular Vibranium shield.
But what’s the back look like? Like this:
Note that it appears to be polished brass for the hero (screencaps), and possibly just gold paint for the other shield (auction photo).