I have never seen one that was delivered unlevel. Tow in and camber issues for sure, but not unlevel. 1" lower is not enough to be concerned about, but when they get to 3" you need to take a look. Most of the time you will not find any external visual evidence of anything being damaged. Only removing the fairing from the gear leg, and possibly removing the gear leg from the airplane will it be evident. All that I have thought were bent, were in fact bent, and after replacement set level again. I can generally tell just watching the airplane taxi in. I have replaced several over the years.