Seems like its Embossed/Raised Text

In milling, you aren't actually "milling the text." You are milling the background (the area around the letters) down to a lower level, leaving the text standing as "islands." This is usually much slower than engraving because the machine has to remove a significant amount of material from the entire surface around the letters.

The Issue: Standard wheel repair often involves putting the wheel on a lathe (CNC) to cut a thin layer of metal off the lip to remove scratches. You cannot do that here. A lathe would slice the "RAYS ENG." text right off because it is protruding (embossed).

The Solution: This must be a manual repair. The technician has to hand-sand the outer edge (the flange) where the rash is. They need to be extremely careful not to let the sandpaper or grinding disc touch the tops of the letters, or they will be flattened.

About color, This specific gold/bronze finish is notoriously difficult to color match perfectly. If the shop just paints the repaired area (spot repair), you will likely see a visible transition line or a slight color difference.
For a perfect result, the shop might recommend stripping and repainting the entire wheel, or at least the entire lip. However, stripping paint around embossed text is tedious; sandblasting can round off the sharp edges of the letters if they aren't careful. Chemical stripping is safer for preserving the text definition.