Yeah, he's actually starting to show some brown striping. He's the darkest boxer I've ever seen in person. Mom was a dark brindle and dad was a light fawn brindle, both with black masks. One other brother came out similar, but not as dark as Cooper did. If I didn't see both parents I would have had a hard time believing he was a boxer myself.
He looks really good out in the sun. I get tons of compliments on how nice his coat looks.