Looks similar to my Koda, just a little darker! I got Koda from Craigslist as well, found out he came with Heartworm that we've obviously treated. Has this guy been given a clean bill of health? Just be weary, people aren't always forthright about why they're giving up their dogs! A lady found Koda as a stay (so she said), which leads me to believe someone dumped him due to the Heartworm...
Not trying to scare you, he's probably fine, but just make sure!
He's beautiful!