What a lovely puppy! The roaning definitely appears as the pup gets older. My blue roan looked black and white when she was born. Her solid black patches were there from birth and the the roaning started to appear quite quickly. She definitely looked like a blue roan by eight weeks.
If the pup is a black and white some of his/her pads will stay pink. What are the parents and do you know which colours they produce? The puppy will be gorgeous whatever the colour!