Yes, they are within the Standard if they are up to 6 pounds. 6 pounds and 1ounce and they are oversized. In the US, that means it would be disqualified. When a Standard says 4 - 6 pounds preferred, that means when all else is equal, you should select the one that's between 4 - 6 pounds. If the better dog is 3 3/4 pounds, then that one would win over a 5 1/2 pound dog of lesser quality. The weight usually comes into play when deciding between equal dogs.
I don't show over there, but in the States, the judges generally will put up a smaller dog before they will put up a smaller bitch. The whole point to conformation shows is to evaluate breeding dogs. It's generally agreed that under 4 pound bitches shouldn't be bred; therefore, judges will overlook a great bitch if she's little. With dogs, they are more leniant because they aren't carrying the litter. That doesn't mean that little can't win. It just means it sometimes takes longer, especially if you show under breeder judges.
Lisa M. Greene
dedicated to Chis for over 25 years
The smallest breed with the biggest heart.