With positive training, you can redirect any bad or inappropriate behaviors you may see. The one good thing about getting an dog that's not a young puppy, is that you can already see his/her personality, which helps when deciding if the dog will fit into your family or not. They have longer attention spans, which makes them a little easier to work with, but yes they may be a little set in their ways. You can still work around that with persistence and consistent training. Don't get frustrated, as the dog will get just as frustrated. Have fun!