Well, it's unlikely to hurt anything to give those supplements. BUT - they're not preventative

The only thing claimed for glucosamine and chondroitin is that they can help relieve
the pain of arthritic joints - not help prevent arthritis (which is the end result of things like hip dysplasia) in the first place. In short, if your dog isn't suffering from arthritic pain, they're not going to do anything for him. And if he has dysplastic hips or is going to develop arthritis, they're not going to stop it. All they'll do is help to reduce the pain and inflammation if and when the condition occurs.