Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I have a friend who works for Apple and he told me what the yellow stickers actually mean.

Apple had supply shortage of iPhone 6s' and to get around this problem they repackaged regular iPhone 6 in the shell of an iPhone 6s. They also managed to falsify the id of the phone in the settings so it claims to be an iPhone 6s.

In other words, enjoy your iPhone 6+
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.