Guys that say they saw a 162" or 163" buck are blowin' smoke. Anyone that has enough experience can make an educated guess that is very close, but when they dub it down to guessing a buck's score (that they saw not killed) to within a point, that's a bit ridiculous. I know some hunters are extremely good a scoring deer before putting a tape on it, but that's after the buck is down and they've had a chance to really exam it.
Personally, I usually give a range....130 to 140 class, etc. there's a less likely chance of being way off :-)