Yes, it is normal. As long as it is not falling out.
He's probably just growing out some new hair , and it is lighter because of the sun and more activity outside. Finn, my 11 month old male, has similar "markings". He was a uniform copper color as a puppy, now he has "texture and highlights".
Those spots are the front and back of his scapula's, so there will be a lot of movement of skin and coat in those areas.
As long as the fur is thick, tight, and not falling out, he's good.
yes, as gunnr mentions it is normal. u can take a soft brush (silicone type, like a glove) and brush him regularly. it helps the old fur the get removed, promotes healthy new fur growth and the color difference to be less visible. and for the pup to get used to grooming too