It can be powder coated.
If it is aluminum it can be anodized.
It can be left raw.
It can be polished.
When dealing with the powdercoater, painter, or anodizing company you can always wheel and deal. One way to do this, is to see if they are doing a batch of xxx color (that you want) and wait until they are doing that color and throw your frame in with that order. Saves them on prep time and can usually pass savings on to you. I did that on a project I did before.