Most hams sold in US grocery stores are precooked, meaning that they have already been cooked and reheating is what you are technically doing to the ham. It is rare to find a raw ham at a regular grocery store. You can look at the label on your ham and it will usually say cured, smoked or baked or obviously precooked. They all mean the same thing, that reheating is what you are doing with the ham itself. This is why we go through the process of heating it using various recipes like this one and making sure that the internal temperature at the end is 145 degrees F. Precooked hams are a way to extend the shelf life of the ham itself. Regardless of what the label says, you will need to cook your ham again to make it warmed and safe to consume.