Must agree with holly, it's absolutely pointless to show in AKC conformation with an altered dog, as it would be an absolute waste of money to compaign a dog to prove it conforms to the standards and then not breed it.
I must say tho, I was at a show a few years back and was watching BIS ring, and the sporting group dog was a lovely golden special. Really, really top notch, beautiful boy, his movement was stunning, and he was in the top 10 (but will remain nameless hehehe)
Anyway, he was stacked and examined, then sent on a down and back, came back up to freestack and the judge stopped him, walked around the dog and asked him to run the down and back again (this is where the dog gaits away from the judge to see rear movement, then turns and comes towards the judge to see front movement) When he came BACK the judge pulled the dog aside and re-evaluated him, then he was excused from the ring among much whispering and hand gestures. Trust me, all spectators where DYING to know what had happened!
Finally, we found out. The dog as a puppy had only one testicle, the other having not dropped fully. The owners decided to put in a neutical. Well at somepoint on the down and back the small un-developed testicle dropped, which happens rarely but DOES happen, and the judge happened to notice an additional "Lump". He was immediatly excused from the ring.... Oops!