Dating an antique horseshoe to a particular time period is challenging. Unlike the mass-produced horseshoes that dominated in the 20th century, blacksmiths forged many antique horseshoes individually and these shoes carry no branding or serial number. What distinguishes an antique horseshoe from a modern horseshoe is the material. In the 19th century, blacksmiths forged horseshoes from iron, while 20th-century manufacturers fabricated modern horseshoes using steel.
It is difficult to tell the difference between a wrought-iron horseshoe and a steel horseshoe by just looking at it. The most-accurate test is the spark test, which is a little destructive. Take an angle grinder to the horseshoe and note the color of the sparks. Modern steel has a high carbon content, and grinding it produces brilliant white sparks. Grinding 19th-century wrought iron produces dull, red sparks. You can also examine the corrosion, though this is a less-accurate test. As 19th-century wrought iron rusts away, the iron silicate becomes exposed. It has a grainy appearance like wood. If a corroded horseshoe looks like rotting wood, then it is likely a wrought-iron horseshoe from the 19th century.