Check out white Scott American Bulldogs on google - I'd say it's more likely your pup is one of those, or a mix, than a Dogo. If he has any Dogo in there, I'd bet he's not pure. Most US Dogos are still cropped, I believe, which would happen before they leave the breeder typically. His structure looks pretty in-line with American Bulldog, too!
Again, only a DNA test would give you more insight, and they're still not going to be 100%.