I believe that you can teach an old dog new tricks so to speak. Some dogs will give a rambunctious pup a pass because it's a pup, but others don't. I've noticed that my oldest is much more lenient with my younger golden then with any other dog ever, I find it almost weird. I think once they get older it's harder but still can be done and carefully.
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD