Jackelope, The only real way to tell is to flip the right ear over and look for a tattoo. All DD's registered in Germany are tattooed before they leave the kennel. I tell people that I spend my weekends out with bearded tattooed ladies, unless I am out with my male DD, Blaze. Then I am just out with one of the guys.
Other than that all DD's are tested and evaluated before you can breed them. The key is that they are truly a versatile dog, I use mine for upland, waterfowl, rabbits and two of them are trained to track blood trails, and the youngest is going to go through that training this spring and summer.
That said they are not for everyone. They need to be challenged all of the time, either in hunting situations or in training.
Lee