Field vs conformation? Hmmm. Not necessarily. It all depends on the dog. Sometimes they have little coat at 5 months and develop a ton of coat. Sometimes they never develop it. Sometimes they have great coat from an early age and never lose it. It just depends on the dog.
Let me show you a few examples. These are all conformation dogs.
Check out this guy. His name was Freedom and he was a conformation dog. In fact, he was THE conformation dog. He was the #1 Golden Retriever show dog in the country for multiple years. Here is what he looked like at 5 months.
Pretty naked compared to how he looked all grown up.
(BTW, the ad in the above photo is by our own Anney Doucette. If you ever need an ad designed, or a logo, or anything having to do with dogs, hit her up. She's awesome.)
But some conformation dogs just never get a lot of coat. Here is one of my dogs at 5 months old.
And here she is last month. She's two years old now, and she still does not have a lot of coat.
So, a lot can change in a few months. Or it might not. Ceegee is right, you can often see a huge difference between 5 and 6 months old, but not always. Dogs are all different.
On the other hand, some dogs have great coat at a very young age, and keep it. Here is Sonny at 5.5 months old. Look at all that coat!
And for reference, here he is grown up.
And here is another of my dogs at 3 months old. This is Gibbs.
And here he is at five months old.
And here he is at about 14 months old.
Quite a difference. So, you just never know. Just love your puppy, and look again when your pup is about three years old. That's when Goldens usually have their full coat.