
The thing is you are judging the dogs against the standard not one another so if one has a missing tooth and the other does not then the one with complete dentition is as stated in the standard the one with a missing tooth is not. However if the tooth was removed because of an accident and the handler has permission to show the missing tooth is then ignored.
Veteran classes are not to award those who have weathered well nor should particular allowance be made for age but just as you expect a puppy to be showing signs of its age, puppy coat or perhaps bum high you expect the veteran to have a white muzzle and looser pasterns but you will still be looking for a typical example that is close to the standard allowing for natural signs of age but non functioning parts or missing ones are not ignored although for me castration would be.
How you present your exhibit in the ring is up to you, clips or cuts may be suggested but are never compulsory so if a dog is shown in puppy clip that is not a problem or at least it would not be for me, mind you my breed is shown in its natural state no matter what the age.