Large breeds as classified by the AKC average over 25" at the shoulder.Yes, I would categorize a lab to be a large breed. We feed our goldens Eagle Pack Holistic for Large and Giant Breeds. Our vet and breeder recommended and approved. Also, my male is 69lbs and female is 60lbs and they are 16 months old which is well within range for their sex and breed.
might i add, I do understand where you are coming from. People will comment on my two goldens and say, Wow, they are big! I really don't see them as being all that big and I know that they are not fat, but compared with a small or toy breed, they do fall into the large breed category!