Will the subject options be available for specification on Model 3?
First, no one knows, so any response will be speculation. Second, I believe that the initial test drive models were wearing 20 inch wheels. That is likely to be the largest size wheel and there is also likely to be a smaller size, probably 18 inches. It stands to reason that gray wheels will be an option, as they are in the model s. All three model 3s at the reveal had different wheels.
Very doubtful Tesla will sell white wheels. They would show dirt and brake dust all the time. White wheels only make sense for show cars that are not driven.