Hi, the pigmentation of the nose colour can change from pink to black and even vice versa, so if the nose does not look hurt, it's probably fine. It could have been a healed up spot too. If Ozzie is in a lot of sun, you should probably put sunscreen on the nose to protect it from sunburn.
2) A transient form of the above condition may exist or it may be something else, but some dogs do lose some pigment and then recover the normal coloring of their nose over time. 3) Labradors, Golden retrievers, Bernese Mountain dogs and Siberian huskies may have seasonal variation in the color of the nasal planum, usually lighter in the winter and darker in the summer. The cause of this is not known, either. Some vets refer to this as "snow nose". "
If it is just one round spot, then more then likely it is an injury. If it is an injury, it will turn black again when it heals. Either way, nothing to worry about. Some goldens have more pigmentation then others.
Our Nugget had the pink pigmentation on his nose for a spell. I don't know if this helped or not but we switched from using a plastic feeding bowl to a steel one and his nose turned back to black and never went pink again. He was probably a little over a year old when this happened.