Hi, C. You can use galvanized pipe but black is acceptable. If you buy "threaded and coupled" pipe, the couplings that come on the pipe are not acceptable and you will have to use new ones.
For what it's worth, the home centers stock some really lousy import pipe and I would not use it. I have seen some with threads that would not seal acceptably, in my opinion. You would be much better to buy your pipe at a plumbing distributor and specify domestic pipe, which is what most of them stock anyway. Don't forget to check all your joints with soapy water after you make up the line.