Who's your daddy?
Not all boxers have underbites, all though most do. Also puppies don't really have one , b/c their jawls and teeth haven't develped enough. I have two purebred boxers and they didn't have underbites as puppies and now they do, but not as prominent as some boxers I have seen. If your dog has a wiggle then he is definetley part boxer. I have noticed that a lot of boxers are mixed with pit bull. Not necessarily a bad thing, but just seems to be that way. I don't see pit bull in your puppy though. Looks more like lab or some mixed breed. Hope this helps.